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Sample records for ir spectrometry method

  1. IDENTIFICATION OF SOME COMPOSITE MEDICINAL DRUGS CONTAINING PARACETAMOL, WITH IR-SPECTROMETRY METHOD

    Directory of Open Access Journals (Sweden)

    A. S. Saushkina

    2017-01-01

    Full Text Available A serious threat to the health of the population is falsified medicines. In a number of cases, they are identified in the process of incoming quality control for compliancewith the requirements of regulatory documents for indicators “Description”, “Packaging”, “Marking”. However, in order to identify sophisticated counterfeits, only a visual assessment of the drug is not enough. Purpose screening evaluation of potentiallycounterfeited or poor-quality drugs using the IR spectrometry along the total spectrum.Materials and methods. The objects of research were available in freely availablecommercially available tablets produced by domestic and foreign manufacturers“Paracetamol Extratab”, “Solpadein fast”, “Citrapac”, “Citramon P”, “Ascofen-P”,  corresponding to the requirements of the current regulatory documents. The studies were carried out on a Fourier-Spectrophotometer infrared “FSM 1201”. Results and discussion. On the example of the tablets “Citramon P”, “Ascophen-P”, “Citrapac”, “Paracetamol Extratab”, “Solpadein Fast” the possibility of using the total IR spectra as a primary screening index of authenticity is shown. It was established that the total IR spectra of medicines of similar composition reflect the similarity of serial samples of the products ofone manufacturer and the difference in serial samples of products of different manufacturers.

  2. Completely automated open-path FT-IR spectrometry.

    Science.gov (United States)

    Griffiths, Peter R; Shao, Limin; Leytem, April B

    2009-01-01

    Atmospheric analysis by open-path Fourier-transform infrared (OP/FT-IR) spectrometry has been possible for over two decades but has not been widely used because of the limitations of the software of commercial instruments. In this paper, we describe the current state-of-the-art of the hardware and software that constitutes a contemporary OP/FT-IR spectrometer. We then describe advances that have been made in our laboratory that have enabled many of the limitations of this type of instrument to be overcome. These include not having to acquire a single-beam background spectrum that compensates for absorption features in the spectra of atmospheric water vapor and carbon dioxide. Instead, an easily measured "short path-length" background spectrum is used for calculation of each absorbance spectrum that is measured over a long path-length. To accomplish this goal, the algorithm used to calculate the concentrations of trace atmospheric molecules was changed from classical least-squares regression (CLS) to partial least-squares regression (PLS). For calibration, OP/FT-IR spectra are measured in pristine air over a wide variety of path-lengths, temperatures, and humidities, ratioed against a short-path background, and converted to absorbance; the reference spectrum of each analyte is then multiplied by randomly selected coefficients and added to these background spectra. Automatic baseline correction for small molecules with resolved rotational fine structure, such as ammonia and methane, is effected using wavelet transforms. A novel method of correcting for the effect of the nonlinear response of mercury cadmium telluride detectors is also incorporated. Finally, target factor analysis may be used to detect the onset of a given pollutant when its concentration exceeds a certain threshold. In this way, the concentration of atmospheric species has been obtained from OP/FT-IR spectra measured at intervals of 1 min over a period of many hours with no operator intervention.

  3. Methods of neutron spectrometry

    International Nuclear Information System (INIS)

    Doerschel, B.

    1981-01-01

    The different methods of neutron spectrometry are based on the direct measurement of neutron velocity or on the use of suitable energy-dependent interaction processes. In the latter case the measuring effect of a detector is connected with the searched neutron spectrum by an integral equation. The solution needs suitable unfolding procedures. The most important methods of neutron spectrometry are the time-of-flight method, the crystal spectrometry, the neutron spectrometry by use of elastic collisions with hydrogen nuclei, and neutron spectrometry with the aid of nuclear reactions, especially of the neutron-induced activation. The advantages and disadvantages of these methods are contrasted considering the resolution, the measurable energy range, the sensitivity, and the experimental and computational efforts. (author)

  4. TIJAH: Embracing IR Methods in XML Databases

    NARCIS (Netherlands)

    List, Johan; Mihajlovic, V.; Ramirez, Georgina; de Vries, A.P.; Hiemstra, Djoerd; Blok, H.E.

    2005-01-01

    This paper discusses our participation in INEX (the Initiative for the Evaluation of XML Retrieval) using the TIJAH XML-IR system. TIJAH's system design follows a `standard' layered database architecture, carefully separating the conceptual, logical and physical levels. At the conceptual level, we

  5. UV and IR laser ablation for inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Smith, M.R.; Koppenaal, D.W.; Farmer, O.T.

    1993-06-01

    Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Evaluation of the ICP/MS mass response allows deductions to be made concerning how representative the laser ablation produced particle plume composition is relative to the targeted sample. Using a black glass standard, elemental fractionation was observed, primarily for alkalis and other volatile elements. The extent of elemental fractionation between the target sample and the sampled plume varied significantly as a function of laser fluences and IR and UV laser frequency

  6. Characterization of a novel miniaturized burst-mode infrared laser system for IR-MALDESI mass spectrometry imaging.

    Science.gov (United States)

    Ekelöf, Måns; Manni, Jeffrey; Nazari, Milad; Bokhart, Mark; Muddiman, David C

    2018-03-01

    Laser systems are widely used in mass spectrometry as sample probes and ionization sources. Mid-infrared lasers are particularly suitable for analysis of high water content samples such as animal and plant tissues, using water as a resonantly excited sacrificial matrix. Commercially available mid-IR lasers have historically been bulky and expensive due to cooling requirements. This work presents a novel air-cooled miniature mid-IR laser with adjustable burst-mode output and details an evaluation of its performance for mass spectrometry imaging. The miniature laser was found capable of generating sufficient energy for complete ablation of animal tissue in the context of an IR-MALDESI experiment with exogenously added ice matrix, yielding several hundred confident metabolite identifications. Graphical abstract The use of a novel miniature 2.94 μm burst-mode laser in IR-MALDESI allows for rapid and sensitive mass spectrometry imaging of a whole mouse.

  7. Thermal structure of the Martian atmosphere retrieved from the IR- spectrometry in the 15 mkm CO2 band

    Science.gov (United States)

    Zasova, L.; Formisano, V.; Grassi, D.; Igantiev, N.; Moroz, V.

    Thermal IR spectrometry is one of the methods of the Martian atmosphere investigation below 55 km. The temperature profiles retrieved from the 15 μm CO2 band may be used for MIRA database. This approach gives the vertical resolution of several kilometers and accuracy of several Kelvins. An aerosol abundance, which influences the temperature profiles, is obtained from the continuum of the same spectrum. It is taken into account in the temperature retrieval procedure in a self- consistent way. Although this method has limited vertical resolution it possesses some advantages. For example, the radio occultation method gives the temperature profiles with higher spectral resolution, but the radio observations are sparse in space and local time. Direct measurements, which give the most accurate results, enable to obtain the temperature profiles only for some chosen points (landing places). Actually, the thermal IR-spectrometry is the only method, which allows to monitor the temperature profiles with good coverage both in space and local time. The first measurements of this kind were fulfilled by IRIS, installed on board of Mariner 9. This spectrometer was characterized by rather high spectral resolution (2.4 cm-1). The temperature profiles vs. local time dependencies for different latitudes and seasons were retrieved, including dust storm conditions, North polar night, Tharsis volcanoes. The obtained temperature profiles have been compared with the temperature profiles for the same conditions, taken from Climate Data Base (European GCM). The Planetary Fourier Spectrometer onboard Mars Express (which is planned to be launched in 2003) has the spectral range 1.2-45 μm and spectral resolution of 1.5 cm- 1. Temperature retrieval is one of the main scientific goals of the experiment. It opens a possibility to get a series of temperature profiles taken for different conditions, which can later be used in MIRA producing.

  8. Quantitative analysis of semivolatile organic compounds in selected fractions of air sample extracts by GC/MI-IR spectrometry

    International Nuclear Information System (INIS)

    Childers, J.W.; Wilson, N.K.; Barbour, R.K.

    1990-01-01

    The authors are currently investigating the capabilities of gas chromatography/matrix isolation infrared (GC/MI-IR) spectrometry for the determination of semivolatile organic compounds (SVOCs) in environmental air sample extracts. Their efforts are focused on the determination of SVOCs such as alkylbenzene positional isomers, which are difficult to separate chromatographically and to distinguish by conventional electron-impact ionization GC/mass spectrometry. They have performed a series of systematic experiments to identify sources of error in quantitative GC/MI-IR analyses. These experiments were designed to distinguish between errors due to instrument design or performance and errors that arise from some characteristic inherent to the GC/MI-IR technique, such as matrix effects. They have investigated repeatability as a function of several aspects of GC/MI IR spectrometry, including sample injection, spectral acquisition, cryogenic disk movement, and matrix deposition. The precision, linearity, dynamic range, and detection limits of a commercial GC/MI-IR system for target SVOCs were determined and compared to those obtained with the system's flame ionization detector. The use of deuterated internal standards in the quantitative GC/MI-IR analysis of selected fractions of ambient air sample extracts will be demonstrated. They will also discuss the current limitations of the technique in quantitative analyses and suggest improvements for future consideration

  9. Infrared spectrometry of Venus: IR Fourier spectrometer on Venera 15 as a precursor of PFS for Venus express

    Science.gov (United States)

    Zasova, L. V.; Moroz, V. I.; Formisano, V.; Ignatiev, N. I.; Khatuntsev, I. V.

    2004-01-01

    Thermal infrared spectrometry in the range 6-40 μm with spectral resolution of 4.5-6.5 cm -1 was realized onboard of Venera 15 for the middle atmosphere of Venus investigations. The 3-D temperature and zonal wind fields ( h, ϕ, LT) in the range 55-100 km and the 3-D aerosol field ( h, ϕ, LT) in the range 55-70 km were retrieved and analyzed. The solar related waves at isobaric levels, generated by the absorbed solar energy, were investigated. In the thermal IR spectral range the, ν1, ν2 and ν3 SO 2 and the H 2O rotational (40 μm) and vibro-rotational (6.3 μm) absorption bands are observed and used for minor compounds retrieval. An advantage of the thermal infrared spectrometry method is that both the temperature and aerosol profiles, which need for retrieval of the vertical profiles of minor compounds, are evaluated from the same spectrum. The Fourier spectrometer on Venera-15 may be considered as a precursor of the Planetary Fourier Spectrometer (PI Prof. V. Formisano), which is included in the payload of the planned Venus Express mission. It has a spectral range 0.9-45 μm, separated into two channels: a short wavelength channel (SWC) in the range 0.9-5 μm and a long wavelength channel (LWC) from 6 to 45 μm, and spectral resolution of 1-2 cm -1. In the history of planetary Fourier spectrometry the PFS is a unique instrument, which possesses a short wavelength channel. A functioning of this instrument on the polar orbit with a good spatial and local time coverage will advance our knowledge in the fundamental problems of the Venus atmosphere.

  10. Numerical method for IR background and clutter simulation

    Science.gov (United States)

    Quaranta, Carlo; Daniele, Gina; Balzarotti, Giorgio

    1997-06-01

    The paper describes a fast and accurate algorithm of IR background noise and clutter generation for application in scene simulations. The process is based on the hypothesis that background might be modeled as a statistical process where amplitude of signal obeys to the Gaussian distribution rule and zones of the same scene meet a correlation function with exponential form. The algorithm allows to provide an accurate mathematical approximation of the model and also an excellent fidelity with reality, that appears from a comparison with images from IR sensors. The proposed method shows advantages with respect to methods based on the filtering of white noise in time or frequency domain as it requires a limited number of computation and, furthermore, it is more accurate than the quasi random processes. The background generation starts from a reticule of few points and by means of growing rules the process is extended to the whole scene of required dimension and resolution. The statistical property of the model are properly maintained in the simulation process. The paper gives specific attention to the mathematical aspects of the algorithm and provides a number of simulations and comparisons with real scenes.

  11. Methods for recalibration of mass spectrometry data

    Science.gov (United States)

    Tolmachev, Aleksey V [Richland, WA; Smith, Richard D [Richland, WA

    2009-03-03

    Disclosed are methods for recalibrating mass spectrometry data that provide improvement in both mass accuracy and precision by adjusting for experimental variance in parameters that have a substantial impact on mass measurement accuracy. Optimal coefficients are determined using correlated pairs of mass values compiled by matching sets of measured and putative mass values that minimize overall effective mass error and mass error spread. Coefficients are subsequently used to correct mass values for peaks detected in the measured dataset, providing recalibration thereof. Sub-ppm mass measurement accuracy has been demonstrated on a complex fungal proteome after recalibration, providing improved confidence for peptide identifications.

  12. Thermal structure of the Martian atmosphere retrieved from the IR spectrometry in the 15 μm CO2 band: input to MIRA

    Science.gov (United States)

    Zasova, L. V.; Formisano, V.; Grassi, D.; Igantiev, N. I.; Moroz, V. I.

    This paper describes one of the sources of the data concerning the thermal structure of the Martian atmosphere, based on the thermal IR spectrometry method. It allows to investigate the Martian atmosphere below 55 km by retrieving the temperature profiles from the 15 μm CO2 band. This approach enables to reach the vertical resolution of several kilometers and the temperature accuracy of several Kelvins. An aerosol abundance, which influences the temperature profile, is obtained from the continuum of the same spectrum parallel with the temperature profile and is taken into account in the temperature retrieval procedure in a self consistent way. Although this method has the limited vertical resolution, it possesses a significant advantage: the thermal IR spectrometry allows to monitor the temperature profiles with a good coverage both in space and local time. The Planetary Fourier spectrometer on board of Mars Express has the spectral range from 250 to 8000 cm-1 and a high spectral resolution of about 2 cm-1. Vertical temperature profiles retrieval is one of the main scientific goals of the experiment. The important data are expected to be obtained on the vertical thermal structure of the atmosphere, and its dependence on latitude, longitude, season, local time, clouds and dust loadings. These results should give a significant input in the future MIRA, being included in the Chapter “Structure of the atmosphere from the surface to 100 km”.

  13. Radioactivity measurements of metallic 192Ir sources by calorimetric methods

    International Nuclear Information System (INIS)

    Genka, Tsuguo; Iwamoto, Seikichi; Takeuchi, Norio

    1992-01-01

    The necessity of establishing the traceability of dose measurement in brachytherapy 192 Ir sources is realized by physicians and researchers in the medical field. Standard sources of various shapes such as open-quotes hairpin,close quotes open-quotes single pin,close quotes open-quotes thin wire,close quotes and open-quotes seedclose quotes for calibrating ionization chambers in hospitals are being demanded. Nominal activities of not only these source products but also the standard sources have been so far specified by open-quotes apparentclose quotes values. Determination of open-quotes absoluteclose quotes activity by an established means such as 4pi-beta-gamma coincidence counting is not practical because quantitative dissolution of metallic iridium is very difficult. We tried to determine the open-quotes absoluteclose quotes activity by a calorimetric method in a fully nondestructive way

  14. Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) for Rapid Determination of Microbial Cell Lipid Content: Correlation with Gas Chromatography-Mass Spectrometry (GC-MS).

    Science.gov (United States)

    Millan-Oropeza, Aaron; Rebois, Rolando; David, Michelle; Moussa, Fathi; Dazzi, Alexandre; Bleton, Jean; Virolle, Marie-Joelle; Deniset-Besseau, Ariane

    2017-10-01

    There is a growing interest worldwide for the production of renewable oil without mobilizing agriculture lands; fast and reliable methods are needed to identify highly oleaginous microorganisms of potential industrial interest. The aim of this study was to demonstrate the relevance of attenuated total reflection (ATR) spectroscopy to achieve this goal. To do so, the total lipid content of lyophilized samples of five Streptomyces strains with varying lipid content was assessed with two classical quantitative but time-consuming methods, gas chromatography-mass spectrometry (GC-MS) and ATR Fourier transform infrared (ATR FT-IR) spectroscopy in transmission mode with KBr pellets and the fast ATR method, often questioned for its lack of reliability. A linear correlation between these three methods was demonstrated allowing the establishment of equations to convert ATR values expressed as CO/amide I ratio, into micrograms of lipid per milligram of biomass. The ATR method proved to be as reliable and quantitative as the classical GC-MS and FT-IR in transmission mode methods but faster and more reproducible than the latter since it involves far less manipulation for sample preparation than the two others. Attenuated total reflection could be regarded as an efficient fast screening method to identify natural or genetically modified oleaginous microorganisms by the scientific community working in the field of bio-lipids.

  15. Method and apparatuses for ion cyclotron spectrometry

    Science.gov (United States)

    Dahl, David A [Idaho Falls, ID; Scott, Jill R [Idaho Falls, ID; McJunkin, Timothy R [Idaho Falls, ID

    2012-03-06

    An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber. The trapping electric field may comprise a field potential that, when taken in cross-section along the z-axis, includes at least one section that is concave down and at least one section that is concave up so that ions traversing the field potential experience a net magnetron effect on a cyclotron frequency of the ions that is substantially equal to zero. Other apparatuses and a method for performing ion cyclotron spectrometry are also disclosed herein.

  16. Statistical methods for mass spectrometry-based clinical proteomics

    NARCIS (Netherlands)

    Kakourou, A.

    2018-01-01

    The work presented in this thesis focuses on methods for the construction of diagnostic rules based on clinical mass spectrometry proteomic data. Mass spectrometry has become one of the key technologies for jointly measuring the expression of thousands of proteins in biological samples.

  17. Structure of the Mesosphere of Venus from the reanalized Venera 15 IR-spectrometry data

    Science.gov (United States)

    Zasova, L. V.; Moroz, V. I.; Ignatiev, N. I.; Khatountsev, I. V.

    1998-09-01

    The results of IR-spectromerty on board VENERA-15 have been reanalyzed. The new data concerned temperature, aerosol, water vapor and thermal zonal wind profiles have been obtained and the latitudinal and local time related variations have been investigated. The cyclostrophic zonal wind fields show the presence of mid-latitudinal jet which changes its position with solar time, so that its altitude and wind speed are correlated and indicated the conservation of angular momentum. The connection between altitude of jet and its velocity shows the flux conservation. The wind velocity in the midlatitudinal jet is correlated with temperature inversion in the "cold collar". The low-latitudinal jet (at about 80 km near 20 deg.) is also connected with inversion in temperature profile observed there.

  18. IR-camera methods for automotive brake system studies

    Science.gov (United States)

    Dinwiddie, Ralph B.; Lee, Kwangjin

    1998-03-01

    Automotive brake systems are energy conversion devices that convert kinetic energy into heat energy. Several mechanisms, mostly related to noise and vibration problems, can occur during brake operation and are often related to non-uniform temperature distribution on the brake disk. These problems are of significant cost to the industry and are a quality concern to automotive companies and brake system vendors. One such problem is thermo-elastic instabilities in brake system. During the occurrence of these instabilities several localized hot spots will form around the circumferential direction of the brake disk. The temperature distribution and the time dependence of these hot spots, a critical factor in analyzing this problem and in developing a fundamental understanding of this phenomenon, were recorded. Other modes of non-uniform temperature distributions which include hot banding and extreme localized heating were also observed. All of these modes of non-uniform temperature distributions were observed on automotive brake systems using a high speed IR camera operating in snap-shot mode. The camera was synchronized with the rotation of the brake disk so that the time evolution of hot regions could be studied. This paper discusses the experimental approach in detail.

  19. Initial study of a method for IR measurements in boilers; Inledande studie av metod foer IR-maetning i aangpannor

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, Martin; Joensson, Magnus; Lundin, Leif [Swedish National Testing and Research Inst., Boraas (Sweden)

    1999-10-01

    The tubes in steam boilers are required to be regularly inspected, in order to find water-side deposits, thinning of walls or material defects. This is for safety, problem-free operation and high availability. No non-destructive method of inspection is available today for finding deposits on the insides of boiler tubes. Nor is there any method that can not only detect deposits on the insides of the tubes but also monitor the tubes' wall thicknesses. A suitable method - reliable, safe, easy to use and cost-efficient - is therefore needed. One such method is to measure the surface temperature of a larger area of the diaphragm wall, using a non-contact method, and from the resulting information to assess the material thickness and possible water-side or steam-side deposits. An IR camera is used for non-contact measurement of the radiated energy from several adjacent surface elements, and thus also of their temperature. The temperature is displayed on the camera's screen to produce a picture of the temperature distribution. This is a well-established method today, and is used in applications such as the steel industry, the electricity industry, electronics and health care. The surface temperatures of the tube walls can be measured by inserting an IR camera on an arm into the combustion chamber, without anyone having to get inside the boiler. The combustion chamber is the part of the boiler that is of main interest for inspection, as it is the easiest to reach. Measurements are facilitated by higher temperatures and thus higher heat fluxes through the tube walls. Diaphragm wall temperatures can be measured quickly and rationally over large areas. Points of interest in inspections include determining where there are water-side deposits in the tubes, where tubes are thin, where flow is obstructed and where there might be material defects. With the exception of material defects, all of these mechanisms result in changes in the surface temperature, which in many

  20. Application of FT-IR Classification Method in Silica-Plant Extracts Composites Quality Testing

    Science.gov (United States)

    Bicu, A.; Drumea, V.; Mihaiescu, D. E.; Purcareanu, B.; Florea, M. A.; Trică, B.; Vasilievici, G.; Draga, S.; Buse, E.; Olariu, L.

    2018-06-01

    Our present work is concerned with the validation and quality testing efforts of mesoporous silica - plant extracts composites, in order to sustain the standardization process of plant-based pharmaceutical products. The synthesis of the silica support were performed by using a TEOS based synthetic route and CTAB as a template, at room temperature and normal pressure. The silica support was analyzed by advanced characterization methods (SEM, TEM, BET, DLS and FT-IR), and loaded with Calendula officinalis and Salvia officinalis standardized extracts. Further desorption studies were performed in order to prove the sustained release properties of the final materials. Intermediate and final product identification was performed by a FT-IR classification method, using the MID-range of the IR spectra, and statistical representative samples from repetitive synthetic stages. The obtained results recommend this analytical method as a fast and cost effective alternative to the classic identification methods.

  1. Aerosol mass spectrometry systems and methods

    Science.gov (United States)

    Fergenson, David P.; Gard, Eric E.

    2013-08-20

    A system according to one embodiment includes a particle accelerator that directs a succession of polydisperse aerosol particles along a predetermined particle path; multiple tracking lasers for generating beams of light across the particle path; an optical detector positioned adjacent the particle path for detecting impingement of the beams of light on individual particles; a desorption laser for generating a beam of desorbing light across the particle path about coaxial with a beam of light produced by one of the tracking lasers; and a controller, responsive to detection of a signal produced by the optical detector, that controls the desorption laser to generate the beam of desorbing light. Additional systems and methods are also disclosed.

  2. The study of the curing of the polyurethane coating by method of IR spectroscopy

    Directory of Open Access Journals (Sweden)

    N. A. Korshunova

    2016-12-01

    Full Text Available The results of the study of the curing process of polyurethane compositions with participation of two different catalysts by the method of IR spectroscopy are given. The time dependences of curing of polyurethane coatings from concentrations of catalysts were determined, on the basis of which the most effective catalyst was selected.

  3. Evaluation of V, Ir, Ru, V-Ir, V-Ru, and W-V as permanent chemical modifiers for the determination of cadmium, lead, and zinc in botanic and biological slurries by electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Acar, Orhan

    2005-01-01

    Permanent modifiers (V, Ir, Ru, V-Ir, V-Ru, and W-V) thermally coated on to platforms of pyrolytic graphite tubes were employed for the determination of Cd, Pb, and Zn in botanic and biological slurries by electrothermal atomic absorption spectrometry (ETAAS). Conventional Pd + Mg(NO 3 ) 2 modifier mixture was also used for the determination of analytes in slurries and digested samples. Optimum masses and mass ratios of permanent modifiers for Cd, Pb, and Zn in slurry sample solutions were investigated. The 280 μg of V, 280 μg of V + 200 μg of Ir, 280 μg of V + 200 μg of Ru or 240 μg of W + 280 μg of V in 0.2% (v/v) Triton X-100 plus 0.5% (v/v) HNO 3 mixture was found as efficient as 5 μg of Pd + 3 μg of Mg(NO 3 ) 2 modifier mixture for obtaining thermal stabilization, and for obtaining best recoveries. Optimization conditions of analytes, such as pyrolysis and atomization temperature, characteristic masses and detection limits, and atomization and background peak profiles were studied with permanent and 5 μg of Pd + 3 μg of Mg(NO 3 ) 2 conventional modifiers and compared with each other. The permanent V-Ir, V-Ru, and W-V modifiers remained stable for approximately 250-300 firings when 20 μl of slurries and digested samples were delivered into the atomizer. In addition, the mixed permanent modifiers increase the tube lifetime by 50-95% when compared with untreated platforms. The characteristic masses and detection limits of analytes (dilution factor of 125 ml g -1 ) obtained with V-Ir based on integrated absorbance as example for 0.8% (m/v) slurries were 1.0 pg and 3 ng g -1 for Cd, 18 pg and 17 ng g -1 for Pb, and 0.7 pg and 4 ng g -1 for Zn, respectively. The results of analytes obtained by employing V-Ir, V-Ru, and W-V permanent modifier mixtures in botanic and biological certified and standard reference materials were in agreement with the certified values of reference materials

  4. Testing and Validation of Computational Methods for Mass Spectrometry.

    Science.gov (United States)

    Gatto, Laurent; Hansen, Kasper D; Hoopmann, Michael R; Hermjakob, Henning; Kohlbacher, Oliver; Beyer, Andreas

    2016-03-04

    High-throughput methods based on mass spectrometry (proteomics, metabolomics, lipidomics, etc.) produce a wealth of data that cannot be analyzed without computational methods. The impact of the choice of method on the overall result of a biological study is often underappreciated, but different methods can result in very different biological findings. It is thus essential to evaluate and compare the correctness and relative performance of computational methods. The volume of the data as well as the complexity of the algorithms render unbiased comparisons challenging. This paper discusses some problems and challenges in testing and validation of computational methods. We discuss the different types of data (simulated and experimental validation data) as well as different metrics to compare methods. We also introduce a new public repository for mass spectrometric reference data sets ( http://compms.org/RefData ) that contains a collection of publicly available data sets for performance evaluation for a wide range of different methods.

  5. Computational methods for protein identification from mass spectrometry data.

    Directory of Open Access Journals (Sweden)

    Leo McHugh

    2008-02-01

    Full Text Available Protein identification using mass spectrometry is an indispensable computational tool in the life sciences. A dramatic increase in the use of proteomic strategies to understand the biology of living systems generates an ongoing need for more effective, efficient, and accurate computational methods for protein identification. A wide range of computational methods, each with various implementations, are available to complement different proteomic approaches. A solid knowledge of the range of algorithms available and, more critically, the accuracy and effectiveness of these techniques is essential to ensure as many of the proteins as possible, within any particular experiment, are correctly identified. Here, we undertake a systematic review of the currently available methods and algorithms for interpreting, managing, and analyzing biological data associated with protein identification. We summarize the advances in computational solutions as they have responded to corresponding advances in mass spectrometry hardware. The evolution of scoring algorithms and metrics for automated protein identification are also discussed with a focus on the relative performance of different techniques. We also consider the relative advantages and limitations of different techniques in particular biological contexts. Finally, we present our perspective on future developments in the area of computational protein identification by considering the most recent literature on new and promising approaches to the problem as well as identifying areas yet to be explored and the potential application of methods from other areas of computational biology.

  6. New advanced in alpha spectrometry by liquid scintillation methods

    International Nuclear Information System (INIS)

    McDowell, W.J.; Case, G.N.

    1979-01-01

    Although the ability to count alpha particles by liquid scintillation methods has been long recognized, limited use has been made of the method because of problems of high background and alpha energy identification. In recent years some new developments in methods of introducing the alpha-emitting nuclide to the scintillator, in detector construction, and in electronics for processing the energy analog and time analog signals from the detector have allowed significant alleviation of the problems of alpha spectrometry by liquid scintillation. Energy resolutions of 200 to 300 keV full peak width at half maximum and background counts of 99% of all beta plus gamma interference is now possible. Alpha liquid scintillation spectrometry is now suitable for a wide range of applications, from the accurate quantitative determination of relatively large amounts of known nuclides in laboratory-generated samples to the detection and identification of very small, subpicocurie amounts of alpha emitters in environmental-type samples. Suitable nuclide separation procedures, sample preparation methods, and instrument configurations are available for a variety of analyses

  7. Mass Spectrometry Coupled Experiments and Protein Structure Modeling Methods

    Directory of Open Access Journals (Sweden)

    Lee Sael

    2013-10-01

    Full Text Available With the accumulation of next generation sequencing data, there is increasing interest in the study of intra-species difference in molecular biology, especially in relation to disease analysis. Furthermore, the dynamics of the protein is being identified as a critical factor in its function. Although accuracy of protein structure prediction methods is high, provided there are structural templates, most methods are still insensitive to amino-acid differences at critical points that may change the overall structure. Also, predicted structures are inherently static and do not provide information about structural change over time. It is challenging to address the sensitivity and the dynamics by computational structure predictions alone. However, with the fast development of diverse mass spectrometry coupled experiments, low-resolution but fast and sensitive structural information can be obtained. This information can then be integrated into the structure prediction process to further improve the sensitivity and address the dynamics of the protein structures. For this purpose, this article focuses on reviewing two aspects: the types of mass spectrometry coupled experiments and structural data that are obtainable through those experiments; and the structure prediction methods that can utilize these data as constraints. Also, short review of current efforts in integrating experimental data in the structural modeling is provided.

  8. Effects of rust in the crack face on crack detection based on Sonic-IR method

    International Nuclear Information System (INIS)

    Harai, Y.; Izumi, Y.; Tanabe, H.; Takamatsu, T.; Sakagami, T.

    2015-01-01

    Sonic-IR, which is based on the thermographic detection of the temperature rise due to frictional heating at the defect faces under ultrasonic excitation, has an advantage in the detection of closed and small defects. However, this method has a lot of nuclear factors relating to heat generation. In this study, effects of rust in the crack faces on the crack detection based on the sonic-IR method is experimentally investigated by using crack specimens. The heat generation by ultrasonic excitation was observed regularly during rust accelerated test using original device. The distribution of temperature change around the crack was changed with the progress of rust. This change in heat generation, it believed to be due to change in the contact state of the crack surface due to rust. As a result, it was found that heat generation by ultrasonic excitation is affected by rust in the crack faces. And it was also found that crack detection can be conducted by sonic-IR even if rust was generated in the crack faces. (author)

  9. Hooked differential mobility spectrometry apparatus and method therefore

    Science.gov (United States)

    Shvartsburg, Alexandre A [Richland, WA; Tang, Keqi [Richland, WA; Ibrahim, Yehia M [Richland, WA; Smith, Richard D [Richland, WA

    2009-02-17

    Disclosed are a device and method for improved interfacing of differential mobility spectrometry (DMS) or field asymmetric waveform ion mobility spectrometry (FAIMS) analyzers of substantially planar geometry to subsequent or preceding instrument stages. Interfacing is achieved using curved DMS elements, where a thick ion beam emitted by planar DMS analyzers or injected into them for ion filtering is compressed to the gap median by DMS ion focusing effect in a spatially inhomogeneous electric field. Resulting thinner beams are more effectively transmitted through necessarily constrained conductance limit apertures to subsequent instrument stages operated at a pressure lower than DMS, and/or more effectively injected into planar DMS analyzers. The technology is synergetic with slit apertures, slit aperture/ion funnels, and high-pressure ion funnel interfaces known in the art which allow for increasing cross-sectional area of MS inlets. The invention may be used in integrated analytical platforms, including, e.g., DMS/MS, LC/DMS/MS, and DMS/IMS/MS that could replace and/or enhance current LC/MS methods, e.g., for proteomics research.

  10. New Isotope Analysis Method: Atom Trap Mass Spectrometry

    International Nuclear Information System (INIS)

    Ko, Kwang Hoon; Park, Hyun Min; Han, Jae Min; Kim, Taek Soo; Cha, Yong Ho; Lim, Gwon; Jeong, Do Young

    2011-01-01

    Trace isotope analysis has been an important role in science, archaeological dating, geology, biology and nuclear industry. Some fission products such as Sr-90, Cs-135 and Kr-85 can be released to the environment when nuclear accident occurs and the reprocessing factory operates. Thus, the analysis of artificially produced radioactive isotopes has been of interest in nuclear industry. But it is difficult to detect them due to low natural abundance less then 10 -10 . In general, radio-chemical method has been applied to detect ultra-trace radio isotopes. But this method has disadvantages of long measurement time for long lived radioisotopes and toxic chemical process for the purification. The Accelerator Mass Spectrometer has high isotope selectivity, but the system is huge and its selectivity is affected by isobars. The laser based method, such as RIMS (Resonance Ionization Mass Spectrometry) has the advantage of isobar-effect free characteristics. But the system size is still huge for high isotope selective system. Recently, ATTA (Atom Trap Trace Analysis) has been successfully applied to detect ultra-trace isotope, Kr-81 and Kr-85. ATTA is the isobar-effect free detection with high isotope selectivity and the system size is small. However, it requires steady atomic beam source during detection, and is not allowed simultaneous detection of several isotopes. In this presentation, we introduce new isotope detection method which is a coupled method of Atom Trap Mass Spectrometry (ATMS). We expect that it can overcome the disadvantage of ATTA while it has both advantages of ATTA and mass spectrometer. The basic concept and the system design will be presented. In addition, the experimental status of ATMS will also be presented

  11. Determination of factors through Monte Carlo method for Fricke dosimetry from 192Ir sources for brachytherapy

    International Nuclear Information System (INIS)

    David, Mariano Gazineu; Salata, Camila; Almeida, Carlos Eduardo

    2014-01-01

    The Laboratorio de Ciencias Radiologicas develops a methodology for the determination of the absorbed dose to water by Fricke chemical dosimetry method for brachytherapy sources of 192 Ir high dose rate and have compared their results with the laboratory of the National Research Council Canada. This paper describes the determination of the correction factors by Monte Carlo method, with the Penelope code. Values for all factors are presented, with a maximum difference of 0.22% for their determination by an alternative way. (author)

  12. Synthesis of lithium silicates by the modified method of combustion. XRD and IR

    International Nuclear Information System (INIS)

    Cruz, D.; Bulbulian, S.

    2002-01-01

    The combustion method is fixed in exothermic reactions for producing ceramic compounds. The precursor solutions are mixtures of metal nitrates and the fuels. This method was modified using non-oxidant compounds as lithium hydroxide and silicide acid and urea as fuel. The precursors were heated during 5 minutes at temperatures between 250 C and 550 C allowing so the mixture combustion. The obtained ceramics were characterized by X-ray diffraction and IR spectroscopy. The sample pollution with carbonates was evaluated and it was found that the presence of these diminish according as increase the calcination temperature. (Author)

  13. Method and equipment for γ background compensation in neutron spectrometry

    International Nuclear Information System (INIS)

    Holman, M.; Marik, P.

    1986-01-01

    The compensation of background gamma radiation in neutron spectrometry is based on the measurement of the total energy spectrum of all protons and electrons, and of the energy spectrum of those protons and neutrons which are in coincidence with the discriminating signal derived from the integral of the counting rate distribution by pulse shape. The benefits of the method consist in the possibility of using standard single-parameter apparatus, in considerably smaller demands on the memory capacity and the possibility of a substantially finer division of the spectrum and more accurate compensation of the background than has been the case with methods used so far. A practical application is shown in a block diagram. (J.B.)

  14. Method for predicting peptide detection in mass spectrometry

    Science.gov (United States)

    Kangas, Lars [West Richland, WA; Smith, Richard D [Richland, WA; Petritis, Konstantinos [Richland, WA

    2010-07-13

    A method of predicting whether a peptide present in a biological sample will be detected by analysis with a mass spectrometer. The method uses at least one mass spectrometer to perform repeated analysis of a sample containing peptides from proteins with known amino acids. The method then generates a data set of peptides identified as contained within the sample by the repeated analysis. The method then calculates the probability that a specific peptide in the data set was detected in the repeated analysis. The method then creates a plurality of vectors, where each vector has a plurality of dimensions, and each dimension represents a property of one or more of the amino acids present in each peptide and adjacent peptides in the data set. Using these vectors, the method then generates an algorithm from the plurality of vectors and the calculated probabilities that specific peptides in the data set were detected in the repeated analysis. The algorithm is thus capable of calculating the probability that a hypothetical peptide represented as a vector will be detected by a mass spectrometry based proteomic platform, given that the peptide is present in a sample introduced into a mass spectrometer.

  15. Authenticity study of Phyllanthus species by NMR and FT-IR techniques coupled with chemometric methods

    International Nuclear Information System (INIS)

    Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G.; Boffo, Elisangela F.; Figueira, Glyn M.

    2012-01-01

    The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, 1 H HR-MAS NMR and 1 H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

  16. Authenticity study of Phyllanthus species by NMR and FT-IR Techniques coupled with chemometric methods

    Directory of Open Access Journals (Sweden)

    Maiara S. Santos

    2012-01-01

    Full Text Available The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as "quebra-pedras" in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques.

  17. Authenticity study of Phyllanthus species by NMR and FT-IR techniques coupled with chemometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Boffo, Elisangela F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Figueira, Glyn M., E-mail: maiarassantos@yahoo.com.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

    2012-07-01

    The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, {sup 1}H HR-MAS NMR and {sup 1}H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

  18. Authenticity study of Phyllanthus species by NMR and FT-IR techniques coupled with chemometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Boffo, Elisangela F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Figueira, Glyn M., E-mail: maiarassantos@yahoo.com.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

    2012-07-01

    The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, {sup 1}H HR-MAS NMR and {sup 1}H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

  19. DEVELOPMENT A METHOD OF IR PASTEURIZATION OF MILK AND COMPREHENSIVE ASSESSMENT OF QUALITY OF THE RESULTING PRODUCT

    Directory of Open Access Journals (Sweden)

    M. S. Babenko

    2013-01-01

    Full Text Available The article is devoted to the question of the relevance of IR pasteurization, a method, and comprehensive assess-ment of the quality of the product in small food enterprises and dairy and cattle farms.

  20. “Contrapuntal Reading” as a Method, an Ethos, and a Metaphor for Global IR

    DEFF Research Database (Denmark)

    Bilgin, Pinar

    2016-01-01

    How to approach Global International Relations (IR)? This is a question asked by students of IR who recognize the limits of our field while expressing their concern that those who strive for a Global IR have been less-than-clear about the “how to?” question. In this article, I point to Edward W. ...

  1. Field Sample Preparation Method Development for Isotope Ratio Mass Spectrometry

    International Nuclear Information System (INIS)

    Leibman, C.; Weisbrod, K.; Yoshida, T.

    2015-01-01

    Non-proliferation and International Security (NA-241) established a working group of researchers from Los Alamos National Laboratory (LANL), Pacific Northwest National Laboratory (PNNL) and Savannah River National Laboratory (SRNL) to evaluate the utilization of in-field mass spectrometry for safeguards applications. The survey of commercial off-the-shelf (COTS) mass spectrometers (MS) revealed no instrumentation existed capable of meeting all the potential safeguards requirements for performance, portability, and ease of use. Additionally, fieldable instruments are unlikely to meet the International Target Values (ITVs) for accuracy and precision for isotope ratio measurements achieved with laboratory methods. The major gaps identified for in-field actinide isotope ratio analysis were in the areas of: 1. sample preparation and/or sample introduction, 2. size reduction of mass analyzers and ionization sources, 3. system automation, and 4. decreased system cost. Development work in 2 through 4, numerated above continues, in the private and public sector. LANL is focusing on developing sample preparation/sample introduction methods for use with the different sample types anticipated for safeguard applications. Addressing sample handling and sample preparation methods for MS analysis will enable use of new MS instrumentation as it becomes commercially available. As one example, we have developed a rapid, sample preparation method for dissolution of uranium and plutonium oxides using ammonium bifluoride (ABF). ABF is a significantly safer and faster alternative to digestion with boiling combinations of highly concentrated mineral acids. Actinides digested with ABF yield fluorides, which can then be analyzed directly or chemically converted and separated using established column chromatography techniques as needed prior to isotope analysis. The reagent volumes and the sample processing steps associated with ABF sample digestion lend themselves to automation and field

  2. Development of a method for determination of fatty acid using FT-IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Dimas Augusto Morozin Zaia

    2011-05-01

    Full Text Available In the present paper a new methodology has been developed for determination of fatty acids in biological systems using FT-IR spectroscopy. For this method is not necessary chromophore reagent or pre sample preparation. Palmitic acid was chosen as standard, because it is found in several biological systems. The FT-IR spectrum of palmitic acid showed two absorption bands in the region of 2852 and 2920 cm-1 attributed to CH stretching. The results for these bands showed that the Beer-Lambert Law was followed in wide range of concentration of palmitic acid (14 to 257 mmol L-1. Potassium ferricyanide (K3[Fe(CN6] was used as internal standard. Several interferents were tested and only cholesterol, ferric chloride (higher concentration, mixture of amino acids for the band at 2919 cm-1 (higher concentration and triglyceride could be interferent if they appear in high concentration. Thus, this new methodology has advantage to be not expensive and simple.

  3. MASS SPECTROMETRY PROTEOMICS METHOD AS A RAPID SCREENING TOOL FOR BACTERIAL CONTAMINATION OF FOOD

    Science.gov (United States)

    2017-06-01

    MASS SPECTROMETRY PROTEOMICS METHOD AS A RAPID SCREENING TOOL FOR BACTERIAL CONTAMINATION OF FOOD ECBC-TR...TITLE AND SUBTITLE Mass Spectrometry Proteomics Method as a Rapid Screening Tool for Bacterial Contamination of Food 5a. CONTRACT NUMBER 5b...the MSPM to correctly classify whether or not food samples were contaminated with Salmonella enterica serotype Newport in this blinded pilot study

  4. Atmospheric pressure photo ionization hydrogen/deuterium exchange mass spectrometry--a method to differentiate isomers by mass spectrometry.

    Science.gov (United States)

    Ahmed, Arif; Kim, Sunghwan

    2013-12-01

    In this report, a method for in-source hydrogen/deuterium (H/D) exchange at atmospheric pressure is reported. The method was named atmospheric pressure photo ionization hydrogen/deuterium exchange mass spectrometry (APPI HDX MS). H/D exchange was performed by mixing samples dissolved in toluene with CH3OD solvent and analyzing the mixture using atmospheric pressure photo ionization mass spectrometry (APPI-MS). The APPI HDX spectra obtained with contact times between the analyte solution and methanol-OD (CH3OD) of atmospheric pressure. H/D exchange can be performed in any laboratory with a mass spectrometer and a commercial APPI source. Using this method, multiple H/D exchanges of aromatic hydrogen and/or H/D exchange of active hydrogen were observed. These results demonstrated that H/D exchange can be used to distinguish between isomers containing primary, secondary, and tertiary amines, as well as pyridine and pyrrole functional groups.

  5. Direct Determination of Molecular Weight Distribution of Calf-Thymus DNAs and Study of Their Fragmentation under Ultrasonic and Low-Energy IR Irradiations. A Charge Detection Mass Spectrometry Investigation.

    Science.gov (United States)

    Halim, Mohammad A; Bertorelle, Franck; Doussineau, Tristan; Antoine, Rodolphe

    2018-06-09

    Calf-thymus (CT-DNA) is widely used as binding agent. The commercial samples are known to be "highly polymerized DNA" samples. CT-DNA is known to be fragile in particular upon ultrasonic wave irradiation. Degradation products might have dramatic consequence on its bio-sensing activity, and an accurate determination of the molecular weight distribution and stability of commercial samples is highly demanded. We investigated the sensitivity of charge detection mass spectrometry (CDMS), a single-molecule MS method, both with single-pass and ion trap CDMS ("Benner" trap) modes to the determination of the composition and stability (under multiphoton IR irradiation) of calf-thymus DNAs. We also investigated the changes of molecular weight distributions in the course of sonication by irradiating ultrasonic wave to CT-DNA. We report for the first time, the direct molecular weight (MW) distribution of DNA sodium salt from calf-thymus revealing two populations at high (~10 MDa) and low (~3 MDa) molecular weights. We evidence a transition between the high-MW to the low-MW distribution, confirming that the low-MW distribution results from degradation of CT-DNA. Finally, we report also IRMPD experiments carried out on trapped single-stranded linear DNAs from calf-thymus allowing to extract their activation energy for unimolecular dissociation. We show that single-pass CDMS is a direct, efficient and accurate MS-based approach to determine the composition of calf-thymus DNAs. Furthermore, ion trap CDMS allows us to evaluate the stability (both under multiphoton IR irradiation and in the course of sonication by irradiating ultrasonic wave) of calf-thymus DNAs. This article is protected by copyright. All rights reserved.

  6. Method of forming half-tone test images in the IR spectrum

    International Nuclear Information System (INIS)

    Glebova, L.N.; Gridin, A.S.; Denisov, V.N.; Dmitriev, I.Yu.; Mochalov, I.V.; Chebotarev, S.A.

    1992-01-01

    Test charts in the form of half-tone IR images, including not only an image of the interference-producing background (the underlying earth's surface and clouds), but also the observation objects, are required for conducting bench tests on the noise immunity of modern optoelectronic equipment designed to solve observation problems under background-interference conditions. The simulation of extended half-tone IR images containing the high spatial frequencies of background formations having an appreciable dynamic range of reproducible radiances is a complex problem in technical and processing aspects. The use of phosphorus as visible-to-IR converters for the creation of IR-background simulators is shown to be possible in principle in this paper. 2 refs., 3 figs

  7. IR thermography methods for evaluation of internal defects in light composite armours

    International Nuclear Information System (INIS)

    Swiderski, W.; Szabra, D.; Szudrowicz, M.

    2009-01-01

    Complete text of publication follows. Light composite armour is a preferred solution against military and paramilitary sources of present threats as the reducing mass of battle vehicles provides a possibility of their quick air-transport. The light armours of these vehicles should be resistant against: common and rifle bullets, grenades, anti-personal mines, IED - improvised explosive devices. The range of military applications anticipated for composite armours covers a broad spectrum of materials and designs. Materials of composite armours include graphite epoxy, glass epoxy and aramid fiber composites. The composites that have been examined can include a variety of defects, such as ballistic impacts, embedded defects, manufacturing defects, thermal damage, moisture ingress and other induced defects. Methods for testing ballistic protection of light armours are known and used. First of all they consist of checking armours resistance against the bullets where the bullet velocity is known. Moreover the V50 velocity is defined during the test. In this method the V 50 velocity of a round or standard fragment is defined (according to STANAG 2920) as the velocity at which armour is penetrated at the probability 50%. The distribution of points hit by bullets or fragments on the surface of an armour is also important. In fact, only correct distribution of these points provides a guaranty for an impartial assessment of tested designs. After hitting by a bullet, shape and size of an area of damage in composite armours depends on the type and design of armour, and type of reinforcing material is particularly important. Knowledge of damage characteristics allows to arrange hitting points to avoid overlapping of damaged areas. Nondestructive testing by using IR thermography methods is very useful in evaluation of internal defects. In the paper we present the dependence between the energy of fragments/or bullets and the dimension of internal defects. (author)

  8. Statistical methods for quantitative mass spectrometry proteomic experiments with labeling

    Directory of Open Access Journals (Sweden)

    Oberg Ann L

    2012-11-01

    Full Text Available Abstract Mass Spectrometry utilizing labeling allows multiple specimens to be subjected to mass spectrometry simultaneously. As a result, between-experiment variability is reduced. Here we describe use of fundamental concepts of statistical experimental design in the labeling framework in order to minimize variability and avoid biases. We demonstrate how to export data in the format that is most efficient for statistical analysis. We demonstrate how to assess the need for normalization, perform normalization, and check whether it worked. We describe how to build a model explaining the observed values and test for differential protein abundance along with descriptive statistics and measures of reliability of the findings. Concepts are illustrated through the use of three case studies utilizing the iTRAQ 4-plex labeling protocol.

  9. Statistical methods for quantitative mass spectrometry proteomic experiments with labeling.

    Science.gov (United States)

    Oberg, Ann L; Mahoney, Douglas W

    2012-01-01

    Mass Spectrometry utilizing labeling allows multiple specimens to be subjected to mass spectrometry simultaneously. As a result, between-experiment variability is reduced. Here we describe use of fundamental concepts of statistical experimental design in the labeling framework in order to minimize variability and avoid biases. We demonstrate how to export data in the format that is most efficient for statistical analysis. We demonstrate how to assess the need for normalization, perform normalization, and check whether it worked. We describe how to build a model explaining the observed values and test for differential protein abundance along with descriptive statistics and measures of reliability of the findings. Concepts are illustrated through the use of three case studies utilizing the iTRAQ 4-plex labeling protocol.

  10. Computational and statistical methods for high-throughput mass spectrometry-based PTM analysis

    DEFF Research Database (Denmark)

    Schwämmle, Veit; Vaudel, Marc

    2017-01-01

    Cell signaling and functions heavily rely on post-translational modifications (PTMs) of proteins. Their high-throughput characterization is thus of utmost interest for multiple biological and medical investigations. In combination with efficient enrichment methods, peptide mass spectrometry analy...

  11. Hot Spots Detection of Operating PV Arrays through IR Thermal Image Using Method Based on Curve Fitting of Gray Histogram

    Directory of Open Access Journals (Sweden)

    Jiang Lin

    2016-01-01

    Full Text Available The overall efficiency of PV arrays is affected by hot spots which should be detected and diagnosed by applying responsible monitoring techniques. The method using the IR thermal image to detect hot spots has been studied as a direct, noncontact, nondestructive technique. However, IR thermal images suffer from relatively high stochastic noise and non-uniformity clutter, so the conventional methods of image processing are not effective. The paper proposes a method to detect hotspots based on curve fitting of gray histogram. The result of MATLAB simulation proves the method proposed in the paper is effective to detect the hot spots suppressing the noise generated during the process of image acquisition.

  12. The application of FT-IR spectrum method in photocuring process for polyester acrylate

    International Nuclear Information System (INIS)

    Cao Jin; Lu Xianliang; Zhang Zhenli

    1995-01-01

    This paper describes that the UV curing process of polyester acrylate can be monitored by measuring the degree of double bonds conversion with FT-IR spectroscopy. The various factors effect the UV curing rate. The relation between the curing rate and the concentration of photoinitiator, crosslinking agent, UV light intensity was discussed. (author)

  13. A Rapid Method of Crude Oil Analysis Using FT-IR Spectroscopy

    African Journals Online (AJOL)

    HP USER

    Nigerian Journal of Basic and Applied Science (June,2016), 24(1): 47-55 ... ABSTRACT: This study determines the viability of the use of Fourier Transform ... IR spectra of Crude oil sample containing a mixture of both degraded (sample 151).

  14. DNA adducts: Mass spectrometry methods and future prospects

    International Nuclear Information System (INIS)

    Farmer, P.B.; Brown, K.; Tompkins, E.; Emms, V.L.; Jones, D.J.L.; Singh, R.; Phillips, D.H.

    2005-01-01

    Detection of DNA adducts is widely used for the monitoring of exposure to genotoxic carcinogens. Knowledge of the nature and amounts of DNA adducts formed in vivo also gives valuable information regarding the mutational effects that may result from particular exposures. The power of mass spectrometry (MS) to achieve qualitative and quantitative analyses of human DNA adducts has increased greatly in recent years with the development of improved chromatographic interfaces and ionisation sources. Adducts have been detected on nucleic acid bases, 2'-deoxynucleosides or 2'-deoxynucleotides, with LC-MS/MS being the favoured technique for many of these analyses. Our current applications of this technique include the determination of N7-(2-carbamoyl-2-hydroxyethyl)-guanine, which was postulated to be found as a DNA repair product in urine following exposure to acrylamide, and of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-7,8-dihydro-2'-deoxyadenosine, as markers of oxidative damage in human lymphocyte DNA. Higher sensitivity (with a detection limit of 1-10 adducts/10 12 nucleotides) may be achieved by the use of accelerator mass spectrometry (AMS), although this requires the presence of certain isotopes, such as [ 14 C], in the material being analysed. In order to make this technique more amenable for studies of human exposure to environmental carcinogens, new postlabelling techniques, incorporating [ 14 C] into specific DNA adducts after formation, are being developed. It is expected that combining the use of advanced MS techniques with existing 32 P-postlabelling and immunochemical methodologies will contribute greatly to the understanding of the burden of human exposure to environmental carcinogens

  15. Demonstration of a collimated in situ method for determining depth distributions using gamma-ray spectrometry

    CERN Document Server

    Benke, R R

    2002-01-01

    In situ gamma-ray spectrometry uses a portable detector to quantify radionuclides in materials. The main shortcoming of in situ gamma-ray spectrometry has been its inability to determine radionuclide depth distributions. Novel collimator designs were paired with a commercial in situ gamma-ray spectrometry system to overcome this limitation for large area sources. Positioned with their axes normal to the material surface, the cylindrically symmetric collimators limited the detection of un attenuated gamma-rays from a selected range of polar angles (measured off the detector axis). Although this approach does not alleviate the need for some knowledge of the gamma-ray attenuation characteristics of the materials being measured, the collimation method presented in this paper represents an absolute method that determines the depth distribution as a histogram, while other in situ methods require a priori knowledge of the depth distribution shape. Other advantages over previous in situ methods are that this method d...

  16. Integration of gas chromatography mass spectrometry methods for differentiating ricin preparation methods.

    Science.gov (United States)

    Wunschel, David S; Melville, Angela M; Ehrhardt, Christopher J; Colburn, Heather A; Victry, Kristin D; Antolick, Kathryn C; Wahl, Jon H; Wahl, Karen L

    2012-05-07

    The investigation of crimes involving chemical or biological agents is infrequent, but presents unique analytical challenges. The protein toxin ricin is encountered more frequently than other agents and is found in the seeds of Ricinus communis, commonly known as the castor plant. Typically, the toxin is extracted from castor seeds utilizing a variety of different recipes that result in varying purity of the toxin. Moreover, these various purification steps can also leave or differentially remove a variety of exogenous and endogenous residual components with the toxin that may indicate the type and number of purification steps involved. We have applied three gas chromatography-mass spectrometry (GC-MS) based analytical methods to measure the variation in seed carbohydrates and castor oil ricinoleic acid, as well as the presence of solvents used for purification. These methods were applied to the same samples prepared using four previously identified toxin preparation methods, starting from four varieties of castor seeds. The individual data sets for seed carbohydrate profiles, ricinoleic acid, or acetone amount each provided information capable of differentiating different types of toxin preparations across seed types. However, the integration of the data sets using multivariate factor analysis provided a clear distinction of all samples based on the preparation method, independent of the seed source. In particular, the abundance of mannose, arabinose, fucose, ricinoleic acid, and acetone were shown to be important differentiating factors. These complementary tools provide a more confident determination of the method of toxin preparation than would be possible using a single analytical method.

  17. Ion counting method and it's operational characteristics in gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Fujii, Toshihiro

    1976-01-01

    Ion counting method with continuous channel electron multiplier which affords the direct detection of very small ion currents and it's operational characteristics were studied in gas chromatography-mass spectrometry. Then this method was applied to the single ion detection technique of GC-MS. A detection limit was measured, using various standard samples of low level concentration. (auth.)

  18. Methods for the analysis of the overlapped peaks in analytical gamma-spectrometry

    International Nuclear Information System (INIS)

    Sterlinski, S.; Wasek, M.

    1989-01-01

    A new simple method for the quantitative analysis of the doublet peaks in Ge(Li) or HPGe gamma-spectrometry is presented. No assumptions on the shape of the peaks in gamma-ray spectra being measured are required. Special feature of the method proposed is its usefulness for the analysis of closed doublets. 7 refs., 6 figs. (author)

  19. Classification of edible oils and modeling of their physico-chemical properties by chemometric methods using mid-IR spectroscopy

    Science.gov (United States)

    Luna, Aderval S.; da Silva, Arnaldo P.; Ferré, Joan; Boqué, Ricard

    This research work describes two studies for the classification and characterization of edible oils and its quality parameters through Fourier transform mid infrared spectroscopy (FT-mid-IR) together with chemometric methods. The discrimination of canola, sunflower, corn and soybean oils was investigated using SVM-DA, SIMCA and PLS-DA. Using FT-mid-IR, DPLS was able to classify 100% of the samples from the validation set, but SIMCA and SVM-DA were not. The quality parameters: refraction index and relative density of edible oils were obtained from reference methods. Prediction models for FT-mid-IR spectra were calculated for these quality parameters using partial least squares (PLS) and support vector machines (SVM). Several preprocessing alternatives (first derivative, multiplicative scatter correction, mean centering, and standard normal variate) were investigated. The best result for the refraction index was achieved with SVM as well as for the relative density except when the preprocessing combination of mean centering and first derivative was used. For both of quality parameters, the best results obtained for the figures of merit expressed by the root mean square error of cross validation (RMSECV) and prediction (RMSEP) were equal to 0.0001.

  20. The study of the radiation chemical transformation of the hexane on the surface of aluminium by IR-spectroscopy method

    International Nuclear Information System (INIS)

    Rimikhanova, A.N.

    2006-01-01

    Full text: In this work the experimental results of the radiation-chemical transformation of hexane on the aluminum surface obtained by IR spectroscopy method at room temperature have been presented. The metallic aluminum plates which was obtained by stage pressing granules by mark of AD-00 with the reflection coefficient R=0,85 in the middle infrared range of waves length λ=15 ± 2,2 mkm were used. As an adsorbate unsaturated vapors of hexane were used, the absorption of which was being carried out at the room temperature by the method. The radiation of system was carried out with γ-quanta of Co 60 with doze rate of 1,03 Gy/s - 1, and the absorbed doze in the system was (0,5-2)10 4 Gy. IR reflection spectra when beams fall on the sample under angle near the slipping were measured in diapason of 3600-650 cm - 1 by the spectrophotometer S pecord 71IR . The radiation chemical decomposition of hexane in heterosystem was being traced in stretching (3000-2700 cm - 1) and deformation (1500-1300 cm - 1) vibration diapasons of C-H bonds. The analysis of IR reflection spectra of Al-ads.hexane heterosystem showed that the main products of radiation chemical transformation are hydrocarbons C1-C5, olefins: propylene, butene-1, hexene-1, transhexene-3 and hydrocarbons more heavy than hexane. In frequency range of 1700-2000 cm - 1 the absorption bands of Al-H vibration which concern to aluminum hydrides are founded. By increasing of radiation dose the tendency of increasing of hydrogen accumulation as aluminum hydrides has been established

  1. [Application of FT-IR pattern recognition method for the quality control of pharmaceutical ingredients].

    Science.gov (United States)

    Horgos, József; Kóger, Péter; Zelkó, Romána

    2009-01-01

    Nowadays infrared spectroscopy and chemometrics have proven their effectiveness for both qualitative and quantitative analyses in different fields like agriculture, food, chemical and oil industry. Furier Transformation Infrared Spectroscopy (FT-IR) combined with Attenuated Total Reflectance (ATR) plate is a fast identification instrument. It is suitable for analysis of solid and liquid phase, too. Associated with chemometrics, it would be a powerful tool for the pharmaceutical wholesalers to detect the insufficient quality of pharmaceutical ingredients. In the present study beside the review of the infra red technology, pharmaceutical ingredients were examined with the help of our spectra library.

  2. MPAI (mass probes aided ionization) method for total analysis of biomolecules by mass spectrometry.

    Science.gov (United States)

    Honda, Aki; Hayashi, Shinichiro; Hifumi, Hiroki; Honma, Yuya; Tanji, Noriyuki; Iwasawa, Naoko; Suzuki, Yoshio; Suzuki, Koji

    2007-01-01

    We have designed and synthesized various mass probes, which enable us to effectively ionize various molecules to be detected with mass spectrometry. We call the ionization method using mass probes the "MPAI (mass probes aided ionization)" method. We aim at the sensitive detection of various biological molecules, and also the detection of bio-molecules by a single mass spectrometry serially without changing the mechanical settings. Here, we review mass probes for small molecules with various functional groups and mass probes for proteins. Further, we introduce newly developed mass probes for proteins for highly sensitive detection.

  3. A simple source preparation method for alpha-ray spectrometry of volcanic rock sample

    International Nuclear Information System (INIS)

    Takahashi, Masaomi; Kurihara, Yuichi; Sato, Jun

    2006-01-01

    A simple source preparation method was developed for the alpha-ray spectrometry to determine U and Th in volcanic rockes. Isolation of U and Th from volcanic rocks was made by use of UTEVA-Spec. resin, extraction chromatograph material. U and Th were extracted by TTA-benzene solution and organic phase was evaporated drop by drop on a hot stainless steel planchet to dryness. This method was found to be effective for the preparation of sources for alpha-ray spectrometry. (author)

  4. The Determination of Composite Elements in Zircaloy-2 by X-Ray Fluorescence and Emission Spectrometry Method

    International Nuclear Information System (INIS)

    Dian Anggraini; Rosika Kriswarini; Yusuf N

    2007-01-01

    Analysis of composing elements in zircaloy-2 has been done by Emission Spectrometry method and X-Ray Fluorescence (XRF). The aim of the analysis is to verify conformity between composing elements in zircaloy-2 and the material certificate. Spectrometry Emission method has higher sensitivity in element determination of a material than that of XRF method, so can be estimated that emission spectrometry method has higher accuracy than that of XRF method. The result of qualitative analysis by Emission Spectrometry indicate that the composing elements in zircaloy-2 were Sn, Cr and Ni. However, the qualitative analysis result by XRF method indicated that the composing elements in zircaloy 2 were Sn, Cr, Ni and Fe. Fe element can not be analysed by Emission Spectrometry method because Emission Spectrometer did not equipped with Fe detector. The quantitative analysis result of the composing elements in the material with both methods showed that Sn, Cr and Ni concentration of zircaloy 2 existed in concentration ranges of the material certificate. Result of statistical test (F and t-test) of analysis result of both methods can be used for analyzing composing elements in zircaloy 2. Emission Spectrometry method was more sensitive and accurate for determining Cr and Ni element in zircaloy 2 than that of emission Spectrometry method but both methods had same accuracy. The precision of measurement of Sn, Cr and Ni element using XRF method was better than that of Emission spectrometry method. (author)

  5. Surface studies on graphite furnace platforms covered with Pd, Rh and Ir as modifiers in graphite furnace atomic absorption spectrometry of tellurium

    Energy Technology Data Exchange (ETDEWEB)

    Pedro, Juana [Area de Química Analítica, Departamento de Química, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829 (S3000GL.N), Santa Fe (Argentina); Stripekis, Jorge [Laboratorio de Análisis de Trazas, Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires (Argentina); Departamento de Ingeniería Química, Instituto Tecnológico de Buenos Aires, Av. Eduardo Madero 399 (1106), Buenos Aires (Argentina); Bonivardi, Adrian [Area de Química Analítica, Departamento de Química, Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santiago del Estero 2829 (S3000GL.N), Santa Fe (Argentina); Tudino, Mabel, E-mail: tudino@qi.fcen.uba.ar [Laboratorio de Análisis de Trazas, Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires (Argentina)

    2015-05-01

    The main objective of this work is the study of correlations between the efficiency of the distribution of the permanent platinum group modifiers Pd, Rh and Ir over the graphite surface with the aim of improving analytical signal of tellurium. Modifier solution was deposited onto the platform and pyrolysed after drying. In the case of Pd, the physical vaporization/deposition technique was also tested. In order to analyze the differences amongst coverings (morphology, topology and distribution), the graphite surfaces were studied with scanning electron microscopy and energy dispersive X-ray microscopy. Micrographs for physical vaporization and pyrolytic deposition of Pd were also analyzed in order to explain the lack of signal obtained for tellurium with the first alternative. Similar micrographs were obtained for pyrolytic deposition of Ir and Rh and then, compared to those of Pd. Ir showed the most homogeneous distribution on the graphite surface and the tallest and sharpest transient. With the aim of improving the analytical signal of tellurium, the correlation between the surface studies and the tellurium transient signal (height, area and shape) is discussed. - Highlights: • Distribution of Rh, Pd and Ir onto graphite furnaces is evaluated by SEM and EDX • Micrographs and spectra showed that surface distribution could influence Te signal. • Ir showed the best signal together with the most homogeneous surface distribution. • Pd-PVD micrographs revealed the absence of graphite and no signal for Te.

  6. Methods of calculus for neutron spectrometry in proportional counters

    International Nuclear Information System (INIS)

    Butragueno, J.L.; Blazquez, J.B.; Barrado, J.M.

    1976-01-01

    Response functions for cylindrical proportional counters with hidrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Montecarlo application and the other one analytical at all. Results of both methods have been compared. (author) [es

  7. Methods of calculus for neutron spectrometry in proportional counters

    International Nuclear Information System (INIS)

    Butragueno Casado, J.L.; Blazquez Martinez, J.B.; Barrado Menendez, J.M.

    1976-01-01

    Response functions for cylindrical proportional counters with hydrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Monte Carlo application and the other one analytica at all. Results of both methods have been compared. (Author)

  8. Structural, spectroscopic (FT-IR, NMR, UV-visible), nonlinear optical (NLO), cytotoxic and molecular docking studies of 4-nitro-isonitrosoacetophenone (ninapH) by DFT method

    Science.gov (United States)

    Kucuk, Ilhan; Kaya, Yunus; Kaya, A. Asli

    2017-07-01

    (4-Nitro-phenyl)-oxo-acetaldehyde oxime (ninapH) is a type of oxime, which has a oxime and α-carbonyl groups. This molecule has been synthesized from literature procedure. The structural properties and conformational behaviors were examined using the density functional theory (DFT) with the B3LYP method combined with the 6-311++G(d,p) basis set. As a result of the conformational studies, the most stable conformer was determined, and then this molecule was optimized with the same basis set. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR, NMR and UV-vis spectrometry. The calculated HOMO and LUMO energies show that charge transfer within the molecule. The first order hyperpolarizability and molecular electrostatic potential (MEP) were also performed. The thermodynamic properties (heat capacity, entropy, and enthalpy) of the ninapH have been calculated at different temperatures, 100-1000 K. In addition, the molecular docking studies have been performed with DNA and protein structures (downloaded from Protein Data Bank).

  9. Improved sample preparation method for environmental plutonium analysis by ICP-SFMS and alpha-spectrometry

    International Nuclear Information System (INIS)

    Varga, Z.; Stefanka, Z.; Suranyi, G.; Vajda, N.

    2007-01-01

    A rapid and simple sample preparation method for plutonium determination in environmental samples by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) and alpha-spectrometry is described. The developed procedure involves a selective CaF 2 co-precipitation for preconcentration followed by extraction chromatographic separation. The proposed method effectively eliminates the possible interferences in mass spectrometric analysis and also removes interfering radionuclides that may disturb alpha-spectrometric measurement. For 239 Pu, 240 Pu and 241 Pu limits of detection of 9.0 fg x g -1 (0.021 mBq), 1.7 fg x g -1 (0.014 mBq) and 3.1 fg x g -1 (11.9 mBq) were achieved by ICP-SFMS, respectively, and 0.02 mBq by alpha-spectrometry. Results of certified reference materials agreed well with the recommended values. (author)

  10. Direct olive oil analysis by mass spectrometry: A comparison of different ambient ionization methods.

    Science.gov (United States)

    Lara-Ortega, Felipe J; Beneito-Cambra, Miriam; Robles-Molina, José; García-Reyes, Juan F; Gilbert-López, Bienvenida; Molina-Díaz, Antonio

    2018-04-01

    Analytical methods based on ambient ionization mass spectrometry (AIMS) combine the classic outstanding performance of mass spectrometry in terms of sensitivity and selectivity along with convenient features related to the lack of sample workup required. In this work, the performance of different mass spectrometry-based methods has been assessed for the direct analyses of virgin olive oil for quality purposes. Two sets of experiments have been setup: (1) direct analysis of untreated olive oil using AIMS methods such as Low-Temperature Plasma Mass Spectrometry (LTP-MS) or paper spray mass spectrometry (PS-MS); or alternatively (2) the use of atmospheric pressure ionization (API) mass spectrometry by direct infusion of a diluted sample through either atmospheric pressure chemical ionization (APCI) or electrospray (ESI) ionization sources. The second strategy involved a minimum sample work-up consisting of a simple olive oil dilution (from 1:10 to 1:1000) with appropriate solvents, which originated critical carry over effects in ESI, making unreliable its use in routine; thus, ESI required the use of a liquid-liquid extraction to shift the measurement towards a specific part of the composition of the edible oil (i.e. polyphenol rich fraction or lipid/fatty acid profile). On the other hand, LTP-MS enabled direct undiluted mass analysis of olive oil. The use of PS-MS provided additional advantages such as an extended ionization coverage/molecular weight range (compared to LTP-MS) and the possibility to increase the ionization efficiency towards nonpolar compounds such as squalene through the formation of Ag + adducts with carbon-carbon double bounds, an attractive feature to discriminate between oils with different degree of unsaturation. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Analysis of boron nitride by flame spectrometry methods

    International Nuclear Information System (INIS)

    Telegin, G.F.; Chapysheva, G.Ya.; Shilkina, N.N.

    1989-01-01

    A rapid method has been developed for determination of free and total boron contents as well as trace impurities in boron nitride by using autoclave sample decomposition followed by atomic emission and atomic absorption determination. The relative standard deviation is not greater than 0.03 in the determination of free boron 0.012 in the determination of total boron content

  12. A general method for targeted quantitative cross-linking mass spectrometry

    Science.gov (United States)

    Chemical cross-linking mass spectrometry (XL-MS) provides protein structural information by identifying covalently linked proximal amino acid residues on protein surfaces. The information gained by this technique is complementary to other structural biology methods such as x-ray crystallography, NM...

  13. Simultaneous determination of seven flavonoids in Epimedium by liquid chromatography-tandem mass spectrometry method

    Institute of Scientific and Technical Information of China (English)

    Cai Sheng Wu; Bao Lin Guo; Yu Xin Sheng; Jin Lan Zhang

    2008-01-01

    In this paper, a sensitive and specific liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and determination of seven flavonoids, namely epimedin A, epimedin B, epimedin C, icariin, sagittatoside B, 2"-0-rhamnosyl icariside II, and baohuoside I in Epimedium from different sources.

  14. Combined IR imaging-neural network method for the estimation of internal temperature in cooked chicken meat

    Science.gov (United States)

    Ibarra, Juan G.; Tao, Yang; Xin, Hongwei

    2000-11-01

    A noninvasive method for the estimation of internal temperature in chicken meat immediately following cooking is proposed. The external temperature from IR images was correlated with measured internal temperature through a multilayer neural network. To provide inputs for the network, time series experiments were conducted to obtain simultaneous observations of internal and external temperatures immediately after cooking during the cooling process. An IR camera working at the spectral band of 3.4 to 5.0 micrometers registered external temperature distributions without the interference of close-to-oven environment, while conventional thermocouples registered internal temperatures. For an internal temperature at a given time, simultaneous and lagged external temperature observations were used as the input of the neural network. Based on practical and statistical considerations, a criterion is established to reduce the nodes in the neural network input. The combined method was able to estimate internal temperature for times between 0 and 540 s within a standard error of +/- 1.01 degree(s)C, and within an error of +/- 1.07 degree(s)C for short times after cooking (3 min), with two thermograms at times t and t+30s. The method has great potential for monitoring of doneness of chicken meat in conveyor belt type cooking and can be used as a platform for similar studies in other food products.

  15. Apparatus and method for transient thermal infrared emission spectrometry

    Science.gov (United States)

    McClelland, John F.; Jones, Roger W.

    1991-12-24

    A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

  16. Apparatus and method for transient thermal infrared spectrometry

    Science.gov (United States)

    McClelland, John F.; Jones, Roger W.

    1991-12-03

    A method and apparatus for enabling analysis of a material (16, 42) by applying a cooling medium (20, 54) to cool a thin surface layer portion of the material and to transiently generate a temperature differential between the thin surface layer portion and the lower portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material. The altered thermal infrared emission spectrum of the material is detected by a spectrometer/detector (28, 50) while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of the emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation, so that the detected altered thermal infrared emission spectrum is indicative of the characteristics relating to the molecular composition of the material.

  17. Review and evaluation of spark source mass spectrometry as an analytical method

    International Nuclear Information System (INIS)

    Beske, H.E.

    1981-01-01

    The analytical features and most important fields of application of spark source mass spectrometry are described with respect to the trace analysis of high-purity materials and the multielement analysis of technical alloys, geochemical and cosmochemical, biological and radioactive materials, as well as in environmental analysis. Comparisons are made to other analytical methods. The distribution of the method as well as opportunities for contract analysis are indicated and developmental tendencies discussed. (orig.) [de

  18. The element analysis of high purity beryllium by method of laser mass-spectrometry

    International Nuclear Information System (INIS)

    Virich, V.D.; Kisel', O.V.; Kovtun, K.V.; Pugachev, N.S.; Yakobson, L.A.

    2003-01-01

    The operation is devoted to examination of a possibility of the analysis of element composition pure and high purity model of a beryllium is model by a method of laser mass spectrometry. The advantages of a method in a part of finding of a small amount of admixtures in comparison with other modes of the analysis are exhibited. The possibility of quantitative definition of a content in beryllium samples of gas-making admixtures-C,N,O surveyed

  19. Evaluation of a method for the determination of chromium in urine by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Garcia, M.; Sardinas, O.; Castaneda, I.; Sanchez, R.

    1990-01-01

    A method for the determination of chromium in urine by atomic absorption spectrometry, using electrothermic atomization with pyrolytic graphite tubes, is proposed. The determinations are performed by standard addition. The method is applicable to biologic monitoring of populations with different degrees of exposition. It is also used in the analysis of chromium in sediments. Results of chromium in urine of a population group non-exposed to the metal are presented. 11 refs

  20. An improved method for statistical analysis of raw accelerator mass spectrometry data

    International Nuclear Information System (INIS)

    Gutjahr, A.; Phillips, F.; Kubik, P.W.; Elmore, D.

    1987-01-01

    Hierarchical statistical analysis is an appropriate method for statistical treatment of raw accelerator mass spectrometry (AMS) data. Using Monte Carlo simulations we show that this method yields more accurate estimates of isotope ratios and analytical uncertainty than the generally used propagation of errors approach. The hierarchical analysis is also useful in design of experiments because it can be used to identify sources of variability. 8 refs., 2 figs

  1. Complementary online aerosol mass spectrometry and offline FT-IR spectroscopy measurements: Prospects and challenges for the analysis of anthropogenic aerosol particle emissions

    Science.gov (United States)

    Faber, Peter; Drewnick, Frank; Bierl, Reinhard; Borrmann, Stephan

    2017-10-01

    The aerosol mass spectrometer (AMS) is well established in investigating highly time-resolved dynamics of submicron aerosol chemical composition including organic aerosol (OA). However, interpretation of mass spectra on molecular level is limited due to strong fragmentation of organic substances and potential reactions inside the AMS ion chamber. Results from complementary filter-based FT-IR absorption measurements were used to explain features in high-resolution AMS mass spectra of different types of OA (e.g. cooking OA, cigarette smoking OA, wood burning OA). Using this approach some AMS fragment ions were validated in this study as appropriate and rather specific markers for a certain class of organic compounds for all particle types under investigation. These markers can therefore be used to get deeper insights in the chemical composition of OA based on AMS mass spectra in upcoming studies. However, the specificity of other fragment ions such as C2H4O2+ (m/z 60.02114) remains ambiguous. In such cases, complementary FT-IR measurements allow the interpretation of highly time-resolved AMS mass spectra at the level of molecular functional groups. Furthermore, this study discusses the challenges in reducing inorganic interferences (e.g. from water and ammonium salts) in FT-IR spectra of atmospheric aerosols to decrease spectral uncertainties for better comparisons and, thus, to get more robust results.

  2. Research on 3-D terrain correction methods of airborne gamma-ray spectrometry survey

    International Nuclear Information System (INIS)

    Liu Yanyang; Liu Qingcheng; Zhang Zhiyong

    2008-01-01

    The general method of height correction is not effectual in complex terrain during the process of explaining airborne gamma-ray spectrometry data, and the 2-D terrain correction method researched in recent years is just available for correction of section measured. A new method of 3-D sector terrain correction is studied. The ground radiator is divided into many small sector radiators by the method, then the irradiation rate is calculated in certain survey distance, and the total value of all small radiate sources is regarded as the irradiation rate of the ground radiator at certain point of aero- survey, and the correction coefficients of every point are calculated which then applied to correct to airborne gamma-ray spectrometry data. The method can achieve the forward calculation, inversion calculation and terrain correction for airborne gamma-ray spectrometry survey in complex topography by dividing the ground radiator into many small sectors. Other factors are considered such as the un- saturated degree of measure scope, uneven-radiator content on ground, and so on. The results of for- ward model and an example analysis show that the 3-D terrain correction method is proper and effectual. (authors)

  3. Cross-method validation as a solution to the problem of excessive simplification of measurement in quantitative IR research

    DEFF Research Database (Denmark)

    Beach, Derek

    2007-01-01

    The purpose of this article is to make IR scholars more aware of the costs of choosing quantitative methods. The article first shows that quantification can have analytical ‘costs’ when the measures created are too simple to capture the essence of the systematized concept that was supposed...... detail based upon a review of the democratic peace literature. I then offer two positive suggestions for a way forward. First, I argue that quantitative scholars should spend more time validating their measures, and in particular should engage in multi-method partnerships with qualitative scholars...... that have a deep understanding of particular cases in order to exploit the comparative advantages of qualitative methodology, using the more accurate qualitative measures to validate their own quantitative measures. Secondly, quantitative scholars should lower their level of ambition given the often poor...

  4. Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionization mass spectrometry.

    NARCIS (Netherlands)

    Rusina, T.; Korytar, P.; de Boer, J.

    2011-01-01

    Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

  5. Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionisation mass spectrometry

    NARCIS (Netherlands)

    Rusina, T.; Korytar, P.; Boer, de J.

    2011-01-01

    Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group

  6. Comparison of Titration ICP and XRF Spectrometry Methods in Determination of Cerium in Lens Polishing Powder

    International Nuclear Information System (INIS)

    Ninlaphruk, Sumalee; Pichestapong, Pipat; Mungpayabal, Harinate; Jiyavaranant, Thitima; Srisukho, Supapan; Chaisai, Prapassurn

    2004-10-01

    Three analytical methods in determination of cerium in cerium oxide separated from monazite ore for producing lens polishing powder were compared. These methods are titration ICP and XRF spectrometry techniques. The cerium oxide sample with estimated 45% cerium content needed to be digested and converted into solution before the analysis. The analytical results shown significantly no difference between each method. However, the titration method was found to be more convenient and suitable for quality control in the production of cerium oxide as it does not require standard cerium and the complicated analytical instruments

  7. Calculation of the band structure of GdCo2, GdRh2 e GdIr2 by the APW method

    International Nuclear Information System (INIS)

    Carvalho, J.A.B. de.

    1974-03-01

    The band structure of GdCo 2 , GdRh 2 , GdIr 2 has been calculated by the APW method. A histogram of the density of states is presented for each compound. The bands are transition-metal-like, with s-d hybridization near the Fermi level. The 5d character near the Fermi level increases as one goes from Co to Ir

  8. Multivariate analysis method for energy calibration and improved mass assignment in recoil spectrometry

    International Nuclear Information System (INIS)

    El Bouanani, Mohamed; Hult, Mikael; Persson, Leif; Swietlicki, Erik; Andersson, Margaretha; Oestling, Mikael; Lundberg, Nils; Zaring, Carina; Cohen, D.D.; Dytlewski, Nick; Johnston, P.N.; Walker, S.R.; Bubb, I.F.; Whitlow, H.J.

    1994-01-01

    Heavy ion recoil spectrometry is rapidly becoming a well established analysis method, but the associated data analysis processing is still not well developed. The pronounced nonlinear response of silicon detectors for heavy ions leads to serious limitation and complication in mass gating, which is the principal factor in obtaining energy spectra with minimal cross talk between elements. To overcome the above limitation, a simple empirical formula with an associated multiple regression method is proposed for the absolute energy calibration of the time of flight-energy dispersive detector telescope used in recoil spectrometry. A radical improvement in mass assignment was realized, which allows a more accurate and improved depth profiling with the important feature of making the data processing much easier. ((orig.))

  9. Fourier Transform Infrared (FT-IR) and Laser Ablation Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) Imaging of Cerebral Ischemia: Combined Analysis of Rat Brain Thin Cuts Toward Improved Tissue Classification.

    Science.gov (United States)

    Balbekova, Anna; Lohninger, Hans; van Tilborg, Geralda A F; Dijkhuizen, Rick M; Bonta, Maximilian; Limbeck, Andreas; Lendl, Bernhard; Al-Saad, Khalid A; Ali, Mohamed; Celikic, Minja; Ofner, Johannes

    2018-02-01

    Microspectroscopic techniques are widely used to complement histological studies. Due to recent developments in the field of chemical imaging, combined chemical analysis has become attractive. This technique facilitates a deepened analysis compared to single techniques or side-by-side analysis. In this study, rat brains harvested one week after induction of photothrombotic stroke were investigated. Adjacent thin cuts from rats' brains were imaged using Fourier transform infrared (FT-IR) microspectroscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The LA-ICP-MS data were normalized using an internal standard (a thin gold layer). The acquired hyperspectral data cubes were fused and subjected to multivariate analysis. Brain regions affected by stroke as well as unaffected gray and white matter were identified and classified using a model based on either partial least squares discriminant analysis (PLS-DA) or random decision forest (RDF) algorithms. The RDF algorithm demonstrated the best results for classification. Improved classification was observed in the case of fused data in comparison to individual data sets (either FT-IR or LA-ICP-MS). Variable importance analysis demonstrated that both molecular and elemental content contribute to the improved RDF classification. Univariate spectral analysis identified biochemical properties of the assigned tissue types. Classification of multisensor hyperspectral data sets using an RDF algorithm allows access to a novel and in-depth understanding of biochemical processes and solid chemical allocation of different brain regions.

  10. Methods of measurement of integral and differential linearity distortions of spectrometry sets

    International Nuclear Information System (INIS)

    Fuan, Jacques; Grimont, Bernard; Marin, Roland; Richard, Jean-Pierre

    1969-05-01

    The objective of this document is to describe different measurement methods, and more particularly to present a software for the processing of obtained results in order to avoid interpretation by the investigator. In a first part, the authors define the parameters of integral and differential linearity, outlines their importance in measurements performed by spectrometry, and describe the use of these parameters. In the second part, they propose various methods of measurement of these linearity parameters, report experimental applications of these methods and compare the obtained results

  11. Investigation of hydrogen adsorption centers on Y2O3 by IR-spectroscopy method in diffusive-scattered light

    International Nuclear Information System (INIS)

    Zubkov, S.A.; Borovkov, V.Yu.

    1985-01-01

    Adsorption of hydrogen and carbon oxide at the yttrium oxide at 80 K (5x30 3 PaH 2 ) and 300 K (6.5x10 2 PaCO) respectively are studied by the method of IR spectroscopy. It is shown, that at the surface of yttrium oxide trained in vacuum at 970 K, at least four types of centres of hydrogen adsorption, able to polarize H-H bond in a molecule, exist. Acid-base couple is the highest polarized centre, in the content of which there is a coordination-unsaturated highly-charged yttrium cation. Low-temperature dissociation of hydrogen on Y 2 O 3 surface occurs on the centres which polarized H-H bond in molecule comparatively slow

  12. Current role of liquid chromatography coupled to mass spectrometry in clinical toxicology screening methods.

    Science.gov (United States)

    Viette, Véronique; Fathi, Marc; Rudaz, Serge; Hochstrasser, Denis; Veuthey, Jean-Luc

    2011-07-01

    Abstract Toxicological screening is the analysis of a biological specimen to detect and identify compounds in patients admitted to the hospital with acute intoxication of unknown origin. The screening of a wide range of toxicologically relevant compounds in biological samples is a serious challenge for clinical laboratories. The high selectivity and sensitivity of liquid chromatography coupled to mass spectrometry or tandem mass spectrometry technology provides an attractive alternative to the current methods. For these reasons, an increasing number of applications for multi-target screening or general screening of unknown compounds in biological matrices are being published. This paper is an overview of sample clean-up, chromatographic separation and mass spectrometry detection procedures which can be combined to obtain screening methods adapted to the constraints and needs of various laboratories, and none specifically in clinical toxicology. Currently the techniques are in the hands of specialists, principally in academic institutes. However, the evolution in technology should allow application of the techniques as a tool in toxicology laboratories and thus more widespread exploitation of their potential.

  13. In-situ spectrometry of {sup 137}Cs in the soil by unfolding method

    Energy Technology Data Exchange (ETDEWEB)

    Fueloep, M; Ragan, P [Inst. of Preventive and Clinical Medicine, 833301 Bratislava (Slovakia); Krnac, S [Slovak Technical Univ., Bratislava (Slovakia)

    1996-12-31

    This contribution is aimed to the possibility of improving the in-situ gamma spectrometry to be independent on a knowledge about a depth distribution of {sup 137}Cs in soil and sufficiently sensitive for the measurement of the post-Chernobyl {sup 137}Cs at present, as well. The depth distribution of {sup 137}Cs averaged over a large area of soil is obtained by unfolding of the detector responses to primary and in soil forward scattered photons. The proposed method employs detector with and without collimator. The {sup 137}Cs distributions obtained in-situ measurements are analysed, and comparisons are made to the results obtained with soil sampling and with standard in-situ spectrometry, as well. 5 figs., 1 tab., 4 refs.

  14. In-situ spectrometry of 137Cs in the soil by unfolding method

    International Nuclear Information System (INIS)

    Fueloep, M.; Ragan, P.; Krnac, S.

    1995-01-01

    This contribution is aimed to the possibility of improving the in-situ gamma spectrometry to be independent on a knowledge about a depth distribution of 137 Cs in soil and sufficiently sensitive for the measurement of the post-Chernobyl 137 Cs at present, as well. The depth distribution of 137 Cs averaged over a large area of soil is obtained by unfolding of the detector responses to primary and in soil forward scattered photons. The proposed method employs detector with and without collimator. The 137 Cs distributions obtained in-situ measurements are analysed, and comparisons are made to the results obtained with soil sampling and with standard in-situ spectrometry, as well. 5 figs., 1 tab., 4 refs

  15. Determination of chlorine in coal by X-ray fluorescence spectrometry method

    Energy Technology Data Exchange (ETDEWEB)

    Marek, S.; Bojarska, K. [Central Mining Institute, Katowice (Poland). Dept. of Environmental Monitoring

    1997-12-31

    Determination of chlorine contents in coal is essential for both environmental protection and its technological use. The existing method of chlorine determination in coal are titration methods which have considerable errors particularly in the low concentration range. The elaborated method with the use of X-ray fluorescence spectrometry in a comparison to the other methods is much faster and has better precision and accuracy. The principle of the method lies in the measurement of X-ray fluorescence radiation intensity which is emitted by chlorine in a sample and its comparison with standards. The calibration of the elaborated XRF method is based on natural coals having various concentrations of chlorine within the whole range of its occurrence in Polish coals. Concentrations for the calibration purpose were obtained by the determination of chlorine contents in selected coals by atomic absorption spectrometry method. The procedure of sample preparation for direct X-ray measurements, instrumental measuring conditions and the way of calibration curve preparation are described in the paper. All X-ray measurements were done with a Phillips sequential X-ray fluorescence spectrometer. A double anode Cr-Au X-ray tube with maximum power 3000 MW was used as the excitation source. 5 figs., 4 tabs.

  16. Determination of ultratrace elements in natural waters by solid-phase extraction and atomic spectrometry methods.

    Science.gov (United States)

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

    2003-01-01

    A study was carried out on the preconcentration of ultratrace amounts of cadmium, lead, manganese, copper and iron from high-salinity aqueous samples and determination by atomic spectrometry methods. Sample volume, amount of resin, loading flow rate, and elution volume were optimized in order to obtain the simultaneous preconcentration of all the analytes. Quantitative recoveries were obtained by using 200 mg of iminodiacetic resin with a loading flow rate of 2 mL min(-1), elution volume of 3 mL and sample volume of 50-450 mL. Only copper in seawater samples was not completely retained by the resin (60-70% recovery), due to unfavorable competition of iminodiacetic-active groups with organically bound metal.To quantify the metals in the eluates, two atomic spectrometry techniques were compared: electrothermal atomization atomic absorption spectrometry (ETAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) with simultaneous CCD detection system. Both techniques are suitable for sample analysis with detection limits of 1.0, 4.7, 3.3, 6.8, and 53 ng L(-1) using ETAAS and 12, 122, 3.4, 17, and 21 ng L(-1) using ICP-OES for Cd, Pb, Mn, Cu, and Fe, respectively. Relative standard deviations of the procedures ranged from 1.7 to 14% at the sub-microg L(-1) concentration level. The accuracy of both methods was verified by analyzing various certified reference materials (river water, estuarine water, coastal and off-shore seawater).

  17. Determination of ultratrace elements in natural waters by solid-phase extraction and atomic spectrometry methods

    Energy Technology Data Exchange (ETDEWEB)

    Grotti, Marco; Abelmoschi, Maria Luisa; Soggia, Francesco; Frache, Roberto [Department of Chemistry and Industrial Chemistry, University of Genoa, Via Dodecaneso, 31-16146, Genoa (Italy)

    2003-01-01

    A study was carried out on the preconcentration of ultratrace amounts of cadmium, lead, manganese, copper and iron from high-salinity aqueous samples and determination by atomic spectrometry methods. Sample volume, amount of resin, loading flow rate, and elution volume were optimized in order to obtain the simultaneous preconcentration of all the analytes. Quantitative recoveries were obtained by using 200 mg of iminodiacetic resin with a loading flow rate of 2 mL min{sup -1}, elution volume of 3 mL and sample volume of 50-450 mL. Only copper in seawater samples was not completely retained by the resin (60-70% recovery), due to unfavorable competition of iminodiacetic-active groups with organically bound metal.To quantify the metals in the eluates, two atomic spectrometry techniques were compared: electrothermal atomization atomic absorption spectrometry (ETAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) with simultaneous CCD detection system. Both techniques are suitable for sample analysis with detection limits of 1.0, 4.7, 3.3, 6.8, and 53 ng L{sup -1} using ETAAS and 12, 122, 3.4, 17, and 21 ng L{sup -1} using ICP-OES for Cd, Pb, Mn, Cu, and Fe, respectively. Relative standard deviations of the procedures ranged from 1.7 to 14% at the sub-{mu}g L{sup -1} concentration level. The accuracy of both methods was verified by analyzing various certified reference materials (river water, estuarine water, coastal and off-shore seawater). (orig.)

  18. IR-spectroscopy as an analytical method for identification of horticultural peat

    International Nuclear Information System (INIS)

    Lehtovaara, J.; Herranen, M.; Nyroenen, T.; MacDonald, A.

    1988-01-01

    The process of selecting different peat types for horticultural purposes involves many physical and chemical determinations. Infrared spectroscopy could be used together with the usual methods for the evaluation of peat quality. Due to the fact that different peats contain different amounts of infrared absorbing functional groups, each peat produces a characteristic spectrum. From the spectrum, one may determine the botanical composition, degree of humification, ash content, cation exchange capacity, nitrogen content and carbon content, of the natural peat. The spectrum also shows whether the peat has been fertilized and limed and in some cases the presence of mineral soil or wetting agent mixed in the peat may be detected

  19. Investigation of Sm(3) and Eu(3) coordination compounds with pyrazolones by IR spectroscopy method

    International Nuclear Information System (INIS)

    Panyushkin, V.T.; Grishenko, T.V.; Afanas'ev, Yu.A.; Garnovskij, A.D.; Osipov, O.A.

    1978-01-01

    The synthesis is described of the coordination nitrate compounds of Sm(3) and Eu(3) with pyrazolones: 4-aminoantipyrine (A), 1-ethylpyridyl- 3-phenyl-pyrazolone-5(B); 1-(3'-ethylpyridyl)-3(phenylamine-n)-pyrazolone-5(C). It has been determined by the infrared spectroscopy method that exocyclic oxygen atom is the place of coordination bond localization in the pentioned compounds. The infrared spectra analysis of complexes in the 1700-1800 cm -1 region makes it possible to mention bidentate character of NO 3 -groups in the studied complex compounds

  20. Fast Atom Bombardment Spectrometry - a novel analytical method for biologically interesting, non-volatile substances

    International Nuclear Information System (INIS)

    Schmid, E.

    1987-03-01

    Today important chemical substances like proteins can be produced easily and in large amounts. The primary structure of proteins can be analysed automatically, however the procedure can take some months of time. A novel method, fast atom bombardment mass spectrometry (FAB-MS) in combination with enzymatic degradation not only decreases the analysis time, but gives also additional information about the primary structure. Especially for the verification of protein structures - which is important for recombinant proteins - FAB-MS is a very useful method. 40 refs., 56 figs. (P.W.)

  1. Comparison of photoacoustic radiometry to gas chromatography/mass spectrometry methods for monitoring chlorinated hydrocarbons

    International Nuclear Information System (INIS)

    Sollid, J.E.; Trujillo, V.L.; Limback, S.P.; Woloshun, K.A.

    1996-01-01

    A comparison of two methods of gas chromatography mass spectrometry (GCMS) and a nondispersive infrared technique, photoacoustic radiometry (PAR), is presented in the context of field monitoring a disposal site. First is presented an historical account describing the site and early monitoring to provide an overview. The intent and nature of the monitoring program changed when it was proposed to expand the Radiological Waste Site close to the Hazardous Waste Site. Both the sampling methods and analysis techniques were refined in the course of this exercise

  2. 29 CFR 2520.104-48 - Alternative method of compliance for model simplified employee pensions-IRS Form 5305-SEP.

    Science.gov (United States)

    2010-07-01

    ... employee pensions-IRS Form 5305-SEP. 2520.104-48 Section 2520.104-48 Labor Regulations Relating to Labor... compliance for model simplified employee pensions—IRS Form 5305-SEP. Under the authority of section 110 of... Security Act of 1974 in the case of a simplified employee pension (SEP) described in section 408(k) of the...

  3. New developments in radiometrics and mass spectrometry methods for radionuclide analysis of environmental samples

    International Nuclear Information System (INIS)

    Povinec, P.P.; LaRosa, J.J.; Lee, S.H.; Wyse, E.

    2002-01-01

    The radionuclide levels observed at present in the environment are very low, therefore high sensitive analytical systems are required for carrying out environmental investigations. One very important recent development in analytical techniques for low-level activity measurements is the production of large volume HPGe detectors (up to 200% relative efficiency to 75 mm diameter x 75 mm long NaI (Tl) crystals). Their high efficiency and excellent energy resolution permit the analyses of various gamma-emitters in composite samples selectively and very often non-destructively (e.g. in sea sediments). However, this technique is restricted to gamma-emitters only (e.g. for 7 Be, 40 K, 54 Mn, 60 Co, 137 Cs, 210 Pb, etc.). Other radionuclides frequently found in the marine environment are the pure beta-emitters, like 3 H, 14 C, 32 Si, 32 P, 90 Sr, 241 Pu, etc., where mainly liquid scintillation counting has made great improvements in recent years. However, for some of these radionuclides mass spectrometry methods represent a real breakthrough in low-level counting, e.g. 3 He in-growth mass spectrometry for 3 H, or accelerator mass spectrometry (AMS) for 14 C

  4. Spectrum unfolding in X-ray spectrometry using the maximum entropy method

    International Nuclear Information System (INIS)

    Fernandez, Jorge E.; Scot, Viviana; Di Giulio, Eugenio

    2014-01-01

    The solution of the unfolding problem is an ever-present issue in X-ray spectrometry. The maximum entropy technique solves this problem by taking advantage of some known a priori physical information and by ensuring an outcome with only positive values. This method is implemented in MAXED (MAXimum Entropy Deconvolution), a software code contained in the package UMG (Unfolding with MAXED and GRAVEL) developed at PTB and distributed by NEA Data Bank. This package contains also the code GRAVEL (used to estimate the precision of the solution). This article introduces the new code UMESTRAT (Unfolding Maximum Entropy STRATegy) which applies a semi-automatic strategy to solve the unfolding problem by using a suitable combination of MAXED and GRAVEL for applications in X-ray spectrometry. Some examples of the use of UMESTRAT are shown, demonstrating its capability to remove detector artifacts from the measured spectrum consistently with the model used for the detector response function (DRF). - Highlights: ► A new strategy to solve the unfolding problem in X-ray spectrometry is presented. ► The presented strategy uses a suitable combination of the codes MAXED and GRAVEL. ► The applied strategy provides additional information on the Detector Response Function. ► The code UMESTRAT is developed to apply this new strategy in a semi-automatic mode

  5. Determination of trace elements in ground water by two preconcentration methods using atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Elhag, A. Y.

    2004-01-01

    This is a comparative study between two different methods of preconcentration done to separate the trace elements cadmium, nickel. chromium, manganese, copper, zinc, and lead in drinking (ground) water samples taken from different locations in Gezira State, central Sudan (the map); these methods are (coprecipitation) with aluminium hydroxide and by Ammonium Pyrrolidine Dithiocarbamate (APDC) using Methyl Isobutyl Ketone (MIBK) as an organic solvent; and subsequent analysis by Atomic Absorption Spectrometry (AAS) for both methods. The result of comparison showed the superiority of the (APDC) coprecipitation method over the aluminium hydroxide coprecipitation method in the total percentage recoveries of the studied trace elements in drinking (ground) water samples, such results confirm previous studies. This study also involves direct analysis of these water samples by atomic absorption spectrometry to determine the concentrations of trace elements Cadmium, Nickel, Chromium, Manganese, Copper, Zinc and Lead and compare it to the corresponding guide line values described by the World Health Organization and the maximum concentrations of trace elements in drinking water permitted by the Sudanese Standards and Metrology Organizations (SSMO), where the concentrations of some elements in some samples were found to be different than the described values by both of the organizations. The study includes a trial to throw light on the effect of the proximity of the water samples sources to the Blue Nile river on its trace elements concentrations; no relation was proved to exist in that respect.(Author)

  6. Total sulfur determination in residues of crude oil distillation using FT-IR/ATR and variable selection methods

    Science.gov (United States)

    Müller, Aline Lima Hermes; Picoloto, Rochele Sogari; Mello, Paola de Azevedo; Ferrão, Marco Flores; dos Santos, Maria de Fátima Pereira; Guimarães, Regina Célia Lourenço; Müller, Edson Irineu; Flores, Erico Marlon Moraes

    2012-04-01

    Total sulfur concentration was determined in atmospheric residue (AR) and vacuum residue (VR) samples obtained from petroleum distillation process by Fourier transform infrared spectroscopy with attenuated total reflectance (FT-IR/ATR) in association with chemometric methods. Calibration and prediction set consisted of 40 and 20 samples, respectively. Calibration models were developed using two variable selection models: interval partial least squares (iPLS) and synergy interval partial least squares (siPLS). Different treatments and pre-processing steps were also evaluated for the development of models. The pre-treatment based on multiplicative scatter correction (MSC) and the mean centered data were selected for models construction. The use of siPLS as variable selection method provided a model with root mean square error of prediction (RMSEP) values significantly better than those obtained by PLS model using all variables. The best model was obtained using siPLS algorithm with spectra divided in 20 intervals and combinations of 3 intervals (911-824, 823-736 and 737-650 cm-1). This model produced a RMSECV of 400 mg kg-1 S and RMSEP of 420 mg kg-1 S, showing a correlation coefficient of 0.990.

  7. A New Method for Processing Airborne Gamma Ray Spectrometry Data for Mapping Low Level Contaminations

    DEFF Research Database (Denmark)

    Aage, Helle Karina; Korsbech, Uffe C C; Bargholz, Kim

    1999-01-01

    A new technique for processing airborne gamma ray spectrometry data has been developed. It is based on the noise adjusted singular value decomposition method introduced by Hovgaard in 1997. The new technique opens for mapping of very low contamination levels. It is tested with data from Latvia...... where the remaining contamination from the 1986 Chernobyl accident together with fallout from the atmospheric nuclear weapon tests includes Cs-137 at levels often well below 1 kBq/m(2) equivalent surface contamination. The limiting factors for obtaining reliable results are radon in the air, spectrum...

  8. Method for detecting binding events using micro-X-ray fluorescence spectrometry

    Science.gov (United States)

    Warner, Benjamin P.; Havrilla, George J.; Mann, Grace

    2010-12-28

    Method for detecting binding events using micro-X-ray fluorescence spectrometry. Receptors are exposed to at least one potential binder and arrayed on a substrate support. Each member of the array is exposed to X-ray radiation. The magnitude of a detectable X-ray fluorescence signal for at least one element can be used to determine whether a binding event between a binder and a receptor has occurred, and can provide information related to the extent of binding between the binder and receptor.

  9. An indirect method for determining phosphorus in aluminium alloys by atomic-absorption spectrometry.

    Science.gov (United States)

    Bernal, J L; Del Nozal, M A; Deban, L; Aller, A J

    1981-07-01

    An indirect method is described for the determination of phosphorus in aluminium alloys. Ammonium molybdate is added to a solution of the aluminium alloy and the molybdophosphoric acid formed is selectively extracted into n-butyl acetate. The twelve molybdenum atoms associated with each phosphate ion are determined by direct atomic-absorption spectrometry with the n-butyl acetate phase in a nitrous oxide-acetylene flame, with measurement at 313.2 nm. The most suitable conditions have been established and the effect of other ions has been studied.

  10. Isotope dilution inductively coupled plasma quadrupole mass spectrometry in connection with a chromatographic separation for ultra trace determinations of platinum group elements (Pt, Pd, Ru, Ir) in environmental samples.

    Science.gov (United States)

    Müller, M; Heumann, K G

    2000-09-01

    An isotope dilution inductively coupled plasma quadrupole mass spectrometric (ID-ICP-QMS) method was developed for the simultaneous determination of the platinum group elements Pt, Pd, Ru, and Ir in environmental samples. Spike solutions, enriched with the isotopes 194Pt, 108Pd, 99Ru, and 191Ir, were used for the isotope dilution step. Interfering elements were eliminated by chromatographic separation using an anion-exchange resin. Samples were dissolved with aqua regia in a high pressure asher. Additional dissolution of possible silicate portions by hydrofluoric acid was usually not necessary. Detection limits of 0.15 ng x g(-1), 0.075 ng x g(-1), and 0.015 ng x g(-1) were achieved for Pt, Pd, Ru, and Ir, respectively, using sample weights of only 0.2 g. The reliability of the ID-ICP-QMS method was demonstrated by analyzing a Canadian geological reference material and by participating in an interlaboratory study for the determination of platinum and palladium in a homogenized road dust sample. Surface soil, sampled at different distances from a highway, showed concentrations in the range of 0.1-87 ng x g(-1). An exponential decrease of the platinum and palladium concentration with increasing distance and a small anthropogenic contribution to the natural background concentration of ruthenium and iridium was found in these samples.

  11. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Science.gov (United States)

    Schindler, Matthias; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-01

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO2 and reduced to graphite to determine 14C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  12. Comparison of sampling methods for radiocarbon dating of carbonyls in air samples via accelerator mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Schindler, Matthias, E-mail: matthias.schindler@physik.uni-erlangen.de; Kretschmer, Wolfgang; Scharf, Andreas; Tschekalinskij, Alexander

    2016-05-15

    Three new methods to sample and prepare various carbonyl compounds for radiocarbon measurements were developed and tested. Two of these procedures utilized the Strecker synthetic method to form amino acids from carbonyl compounds with either sodium cyanide or trimethylsilyl cyanide. The third procedure used semicarbazide to form crystalline carbazones with the carbonyl compounds. The resulting amino acids and semicarbazones were then separated and purified using thin layer chromatography. The separated compounds were then combusted to CO{sub 2} and reduced to graphite to determine {sup 14}C content by accelerator mass spectrometry (AMS). All of these methods were also compared with the standard carbonyl compound sampling method wherein a compound is derivatized with 2,4-dinitrophenylhydrazine and then separated by high-performance liquid chromatography (HPLC).

  13. Absolute quantification method and validation of airborne snow crab allergen tropomyosin using tandem mass spectrometry

    International Nuclear Information System (INIS)

    Rahman, Anas M. Abdel; Lopata, Andreas L.; Randell, Edward W.; Helleur, Robert J.

    2010-01-01

    Measuring the levels of the major airborne allergens of snow crab in the workplace is very important in studying the prevalence of crab asthma in workers. Previously, snow crab tropomyosin (SCTM) was identified as the major aeroallergen in crab plants and a unique signature peptide was identified for this protein. The present study advances our knowledge on aeroallergens by developing a method of quantification of airborne SCTM by using isotope dilution mass spectrometry. Liquid chromatography tandem mass spectrometry was developed for separation and analysis of the signature peptides. The tryptic digestion conditions were optimized to accomplish complete digestion. The validity of the method was studied using international conference on harmonization protocol, Where 2-9% for CV (precision) and 101-110% for accuracy, at three different levels of quality control. Recovery of the spiked protein from PTFE and TopTip filters was measured to be 99% and 96%, respectively. To further demonstrate the applicability and the validity of the method for real samples, 45 kg of whole snow crab were processed in an enclosed (simulated) crab processing line and air samples were collected. The levels of SCTM ranged between 0.36-3.92 μg m -3 and 1.70-2.31 μg m -3 for butchering and cooking stations, respectively.

  14. Dereplication of plant phenolics using a mass-spectrometry database independent method.

    Science.gov (United States)

    Borges, Ricardo M; Taujale, Rahil; de Souza, Juliana Santana; de Andrade Bezerra, Thaís; Silva, Eder Lana E; Herzog, Ronny; Ponce, Francesca V; Wolfender, Jean-Luc; Edison, Arthur S

    2018-05-29

    Dereplication, an approach to sidestep the efforts involved in the isolation of known compounds, is generally accepted as being the first stage of novel discoveries in natural product research. It is based on metabolite profiling analysis of complex natural extracts. To present the application of LipidXplorer for automatic targeted dereplication of phenolics in plant crude extracts based on direct infusion high-resolution tandem mass spectrometry data. LipidXplorer uses a user-defined molecular fragmentation query language (MFQL) to search for specific characteristic fragmentation patterns in large data sets and highlight the corresponding metabolites. To this end, MFQL files were written to dereplicate common phenolics occurring in plant extracts. Complementary MFQL files were used for validation purposes. New MFQL files with molecular formula restrictions for common classes of phenolic natural products were generated for the metabolite profiling of different representative crude plant extracts. This method was evaluated against an open-source software for mass-spectrometry data processing (MZMine®) and against manual annotation based on published data. The targeted LipidXplorer method implemented using common phenolic fragmentation patterns, was found to be able to annotate more phenolics than MZMine® that is based on automated queries on the available databases. Additionally, screening for ascarosides, natural products with unrelated structures to plant phenolics collected from the nematode Caenorhabditis elegans, demonstrated the specificity of this method by cross-testing both groups of chemicals in both plants and nematodes. Copyright © 2018 John Wiley & Sons, Ltd.

  15. Absolute quantification method and validation of airborne snow crab allergen tropomyosin using tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Anas M. Abdel, E-mail: anasar@mun.ca [Department of Chemistry, Memorial University of Newfoundland, St. John' s, Newfoundland A1B 3X7 (Canada); Lopata, Andreas L. [School of Applied Science, Marine Biomedical Sciences and Health Research Group, RMIT University, Bundoora, 3083 Victoria (Australia); Randell, Edward W. [Department of Laboratory Medicine, Memorial University of Newfoundland, Eastern Health, St. John' s, Newfoundland and Labrador A1B 3V6 (Canada); Helleur, Robert J. [Department of Chemistry, Memorial University of Newfoundland, St. John' s, Newfoundland A1B 3X7 (Canada)

    2010-11-29

    Measuring the levels of the major airborne allergens of snow crab in the workplace is very important in studying the prevalence of crab asthma in workers. Previously, snow crab tropomyosin (SCTM) was identified as the major aeroallergen in crab plants and a unique signature peptide was identified for this protein. The present study advances our knowledge on aeroallergens by developing a method of quantification of airborne SCTM by using isotope dilution mass spectrometry. Liquid chromatography tandem mass spectrometry was developed for separation and analysis of the signature peptides. The tryptic digestion conditions were optimized to accomplish complete digestion. The validity of the method was studied using international conference on harmonization protocol, Where 2-9% for CV (precision) and 101-110% for accuracy, at three different levels of quality control. Recovery of the spiked protein from PTFE and TopTip filters was measured to be 99% and 96%, respectively. To further demonstrate the applicability and the validity of the method for real samples, 45 kg of whole snow crab were processed in an enclosed (simulated) crab processing line and air samples were collected. The levels of SCTM ranged between 0.36-3.92 {mu}g m{sup -3} and 1.70-2.31 {mu}g m{sup -3} for butchering and cooking stations, respectively.

  16. Comprehension of complex biological processes by analytical methods: how far can we go using mass spectrometry?

    International Nuclear Information System (INIS)

    Gerner, C.

    2013-01-01

    Comprehensive understanding of complex biological processes is the basis for many biomedical issues of great relevance for modern society including risk assessment, drug development, quality control of industrial products and many more. Screening methods provide means for investigating biological samples without research hypothesis. However, the first boom of analytical screening efforts has passed and we again need to ask whether and how to apply screening methods. Mass spectrometry is a modern tool with unrivalled analytical capacities. This applies to all relevant characteristics of analytical methods such as specificity, sensitivity, accuracy, multiplicity and diversity of applications. Indeed, mass spectrometry qualifies to deal with complexity. Chronic inflammation is a common feature of almost all relevant diseases challenging our modern society; these diseases are apparently highly diverse and include arteriosclerosis, cancer, back pain, neurodegenerative diseases, depression and other. The complexity of mechanisms regulating chronic inflammation is the reason for the practical challenge to deal with it. The presentation shall give an overview of capabilities and limitations of the application of this analytical tool to solve critical questions with great relevance for our society. (author)

  17. Simple methods via Mid-IR or {sup 1}H NMR spectroscopy for the determination of the iodine value of vegetable oils

    Energy Technology Data Exchange (ETDEWEB)

    Shimamoto, Gustavo G.; Favaro, Martha M.A.; Tubino, Matthieu, E-mail: tubino@iqm.unicamp.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Instituto de Química

    2015-07-01

    Two methods for determining the iodine value in vegetable oils are described. One employs mid-infrared (mid-IR) spectroscopy and the other uses hydrogen nuclear magnetic resonance ({sup 1}H NMR). The determination of the iodine value is based on either the transmittance intensity of mid-IR signals or on the {sup 1}H NMR signal integration and multivariate calibration. Both of the methods showed adequate coefficients of determination (r{sup 2} = 0.9974 and 0.9978, respectively) when compared to Wijs method, which is recommended by the norm EN 14111. A statistical comparison between the results from the proposed methods and from Wijs method shows that both instrumental methods offer equivalent results and greater precision compared to Wijs method. The regressions obtained from the constructed models were considered statistically significant and useful for making predictions. The proposed methods present several advantages compared to Wijs method because they significantly reduce analysis time, reagent consumption and waste generation. Furthermore, an analyst can choose between the mid-IR or {sup 1}H NMR to determine the iodine value. (author)

  18. Discrimination of edible oils and fats by combination of multivariate pattern recognition and FT-IR spectroscopy: A comparative study between different modeling methods

    Science.gov (United States)

    Javidnia, Katayoun; Parish, Maryam; Karimi, Sadegh; Hemmateenejad, Bahram

    2013-03-01

    By using FT-IR spectroscopy, many researchers from different disciplines enrich the experimental complexity of their research for obtaining more precise information. Moreover chemometrics techniques have boosted the use of IR instruments. In the present study we aimed to emphasize on the power of FT-IR spectroscopy for discrimination between different oil samples (especially fat from vegetable oils). Also our data were used to compare the performance of different classification methods. FT-IR transmittance spectra of oil samples (Corn, Colona, Sunflower, Soya, Olive, and Butter) were measured in the wave-number interval of 450-4000 cm-1. Classification analysis was performed utilizing PLS-DA, interval PLS-DA, extended canonical variate analysis (ECVA) and interval ECVA methods. The effect of data preprocessing by extended multiplicative signal correction was investigated. Whilst all employed method could distinguish butter from vegetable oils, iECVA resulted in the best performances for calibration and external test set with 100% sensitivity and specificity.

  19. Electrochemical preconcentration and hydride generation methods for trace determination of selenium by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Bye, R.

    1986-01-01

    The use of atomic absorption spectrometry in combination with two different preconcentration/separation techniques for the determination of trace concentrations of selenium is described. Electrochemical preconcentration onto a platinum electrode with a subsequent atomization of selenium is discussed briefly. Several parameters are considered such as the presence of depolarizers, and the temperature of the electrolyzed solutions. Special attention is payed to the efficiency of the atomization step, and a method to improve this is proposed. Applications of the technique to real samples are also reported. Secondly, the separation of the selenium as the volatile selenium hydride from the sample solution is considered. Several papers in this thesis deal with commonly occurring interferants as nickel and copper and with ways of minimizing or avoiding the interferring effects, whereas other papers relate to more theoretical aspects of the hydride generation process. New methods for the determination of selenium in technical samples with high contents of nickel and copper are also presented

  20. An intelligent detection method for high-field asymmetric waveform ion mobility spectrometry.

    Science.gov (United States)

    Li, Yue; Yu, Jianwen; Ruan, Zhiming; Chen, Chilai; Chen, Ran; Wang, Han; Liu, Youjiang; Wang, Xiaozhi; Li, Shan

    2018-04-01

    In conventional high-field asymmetric waveform ion mobility spectrometry signal acquisition, multi-cycle detection is time consuming and limits somewhat the technique's scope for rapid field detection. In this study, a novel intelligent detection approach has been developed in which a threshold was set on the relative error of α parameters, which can eliminate unnecessary time spent on detection. In this method, two full-spectrum scans were made in advance to obtain the estimated compensation voltage at different dispersion voltages, resulting in a narrowing down of the whole scan area to just the peak area(s) of interest. This intelligent detection method can reduce the detection time to 5-10% of that of the original full-spectrum scan in a single cycle.

  1. Standard test method for quantitative determination of americium 241 in plutonium by Gamma-Ray spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This test method covers the quantitative determination of americium 241 by gamma-ray spectrometry in plutonium nitrate solution samples that do not contain significant amounts of radioactive fission products or other high specific activity gamma-ray emitters. 1.2 This test method can be used to determine the americium 241 in samples of plutonium metal, oxide and other solid forms, when the solid is appropriately sampled and dissolved. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  2. Methods of direct (non-chromatographic) quantification of body metabolites utilizing chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Mee, J.M.L.

    1978-01-01

    For quantitative determination of known metabolites from the biological sample by direct chemical ionization mass spectrometry (CI-MS), the method of internal standard using stable isotopically labelled analogs appears to be the method of choice. In the case where stable isotope ratio determinations could not be applied, and alternative quantification can be achieved using non-labelled external or internal standards and a calibration curve (sum of peak height per a given number of scans versus concentration). The technique of computer monitoring permits display and plotting of ion current profiles (TIC and SIC) or spectra per a given number of scans or a given range of mass per charge. Examples are given in areas of clinical application and the quantitative data show very good agreement with the conventional chromatographic measurements. (Auth.)

  3. Standard test method for the radiochemical determination of americium-241 in soil by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This method covers the determination of americium–241 in soil by means of chemical separations and alpha spectrometry. It is designed to analyze up to ten grams of soil or other sample matrices that contain up to 30 mg of combined rare earths. This method allows the determination of americium–241 concentrations from ambient levels to applicable standards. The values stated in SI units are to be regarded as standard. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precaution statements, see Section 10.

  4. The Ramsey method in high-precision mass spectrometry with Penning traps Experimental results

    CERN Document Server

    George, S; Herfurth, F; Herlert, A; Kretzschmar, M; Nagy, S; Schwarz, S; Schweikhard, L; Yazidjian, C

    2007-01-01

    The highest precision in direct mass measurements is obtained with Penning trap mass spectrometry. Most experiments use the interconversion of the magnetron and cyclotron motional modes of the stored ion due to excitation by external radiofrequency-quadrupole fields. In this work a new excitation scheme, Ramsey's method of time-separated oscillatory fields, has been successfully tested. It has been shown to reduce significantly the uncertainty in the determination of the cyclotron frequency and thus of the ion mass of interest. The theoretical description of the ion motion excited with Ramsey's method in a Penning trap and subsequently the calculation of the resonance line shapes for different excitation times, pulse structures, and detunings of the quadrupole field has been carried out in a quantum mechanical framework and is discussed in detail in the preceding article in this journal by M. Kretzschmar. Here, the new excitation technique has been applied with the ISOLTRAP mass spectrometer at ISOLDE/CERN fo...

  5. Isotope-dilution gas chromatography-mass spectrometry method for the analysis of hydroxyurea.

    Science.gov (United States)

    Garg, Uttam; Scott, David; Frazee, Clint; Kearns, Gregory; Neville, Kathleen

    2015-06-01

    Hydroxyurea is used in the treatment of various malignancies and sickle cell disease. There are limited studies on the pharmacokinetics of hydroxyurea, particularly in pediatric patients. An accurate, precise, and sensitive method is needed to support such studies and to monitor therapeutic adherence. We describe a novel gas chromatography-mass spectrometry (GC-MS) method for the determination of hydroxyurea concentration in plasma using stable labeled hydroxyurea C N2 as an internal standard. The method involved an organic extraction followed by the preparation of trimethylsilyl (TMS) derivatives of hydroxyurea for GC-MS selected ion-monitoring analysis. The following mass-to-charge (m/z) ratio ions for silated hydroxyurea and hydroxyurea C N2 were monitored: hydroxyurea-quantitative ion 277, qualifier ions 292 and 249; hydroxyurea C N2-quantitative ion 280, qualifier ion 295. This method was evaluated for reportable range, accuracy, within-run and between-run imprecisions, and limits of quantification. The reportable range for the method was 0.1-100 mcg/mL. All results were accurate within an allowable error of 15%. Within-run and between-run imprecisions were hydroxyurea described here is accurate, sensitive, precise, and robust. Its characteristics make the method suitable for supporting pharmacokinetic studies and/or clinical therapeutic monitoring.

  6. The former Semipalatinsk Test Site survey by field γ-spectrometry method

    International Nuclear Information System (INIS)

    Pakhomov, S.A.; Dubasov, Yu.V.; Biryukov, E.I.; Gavrilin, S.S.; Ilyin, L.I.

    2001-01-01

    Full text: Field γ-spectrometry method is the most productive method of getting an information on gamma-irradiating radionuclides contents in objects under survey. For many years the Radium Institute was the most active participant of works on radiation survey of the Semipalatinsk Test Site, field γ-spectrometry method including. In field γ-spectrometry method realization the existence of corresponding apparatus, and methodic software is supposed to be allowing to carry out both measurement, recording of γ-spectrometry energetic characteristics in field conditions and final treatment (using corresponding physical models) ensuring obtaining the information on radionuclides' contents. Different variants of such apparatus were developed and made at the Radium Institute. Under conditions of complex spectral structure and high intensity existence a portable variant of Ge(Li)-detector spectrometer fed by alkaline accumulators and allowing to record a spectrum at high load was elaborated. For walk γ-survey in common with the University two variants of portable spectrometers 'Skif-3' were elaborated: one of them with a standard scintillation detector on the base of Nal(Ti) crystal, having the size of 63x63 mm, and the other is an 'X-ray' detector of large dimension on the base of CsI crystal with a diameter of 165 mm, designated for soft gamma-irradiation registration, 241 Am including. During 8 hours of independent works 'Skif-3' is able to record into internal memory up to 100 spectra with an exposure up to 9999 s. At 10 min exposure in its sensitivity of 241 Am finding (10 Bq/kg) a spectrometer 'Skif-3' excels a portable spectrometer 'InSpector' (Canberra) working with the exposure of 1 hour. For automobile measurements a car spectrometer was elaborated fed. from car board supply and having four detectors based on NaI crystals with the dimensions 200x110 mm and total volume of about 121. For express treatment of a 'Skif-3' spectrometer scintillation spectra special

  7. Change detection by the IR-MAD and kernel MAF methods in Landsat TM data covering a Swedish forest region

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Olsson, Håkan

    2010-01-01

    Change over time between two 512 by 512 (25 m by 25 m pixels) multispectral Landsat Thematic Mapper images dated 6 June 1986 and 27 June 1988 respectively covering a forested region in northern Sweden, is here detected by means of the iteratively reweighted multivariate alteration detection (IR-M...

  8. Room-temperature quantum noise limited spectrometry and methods of the same

    Science.gov (United States)

    Stevens, Charles G.; Tringe, Joseph W.; Cunningham, Christopher T.

    2018-05-15

    According to one embodiment, a heterodyne detection system for detecting light, includes: a first input aperture configured to receive first light from a scene input; a second input aperture configured to receive second light from a local oscillator input; a broadband local oscillator configured to provide the second light to the second input aperture; a dispersive element configured to disperse the first light and the second light; and a final condensing lens coupled to a detector. The final condensing lens is configured to concentrate incident light from a primary condensing lens onto the detector. The detector is configured to sense a frequency difference between the first light and the second light; and the final condensing lens comprises a plasmonic condensing lens. Methods for forming a plasmonic condensing lens to enable room temperature quantum noise limited spectrometry are also disclosed.

  9. A General Method for Targeted Quantitative Cross-Linking Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Juan D Chavez

    Full Text Available Chemical cross-linking mass spectrometry (XL-MS provides protein structural information by identifying covalently linked proximal amino acid residues on protein surfaces. The information gained by this technique is complementary to other structural biology methods such as x-ray crystallography, NMR and cryo-electron microscopy[1]. The extension of traditional quantitative proteomics methods with chemical cross-linking can provide information on the structural dynamics of protein structures and protein complexes. The identification and quantitation of cross-linked peptides remains challenging for the general community, requiring specialized expertise ultimately limiting more widespread adoption of the technique. We describe a general method for targeted quantitative mass spectrometric analysis of cross-linked peptide pairs. We report the adaptation of the widely used, open source software package Skyline, for the analysis of quantitative XL-MS data as a means for data analysis and sharing of methods. We demonstrate the utility and robustness of the method with a cross-laboratory study and present data that is supported by and validates previously published data on quantified cross-linked peptide pairs. This advance provides an easy to use resource so that any lab with access to a LC-MS system capable of performing targeted quantitative analysis can quickly and accurately measure dynamic changes in protein structure and protein interactions.

  10. Methods of analysis-Determination of pesticides in sediment using gas chromatography/mass spectrometry

    Science.gov (United States)

    Hladik, Michelle; McWayne, Megan M.

    2012-01-01

    A method for the determination of 119 pesticides in environmental sediment samples is described. The method was developed by the U.S. Geological Survey (USGS) in support of the National Water Quality Assessment (NAWQA) Program. The pesticides included in this method were chosen through prior prioritization. Herbicides, insecticides, and fungicides along with degradates are included in this method and span a variety of chemical classes including, but not limited to, chloroacetanilides, organochlorines, organophosphates, pyrethroids, triazines, and triazoles. Sediment samples are extracted by using an accelerated solvent extraction system (ASE®, and the compounds of interest are separated from co-extracted matrix interferences (including sulfur) by passing the extracts through high performance liquid chromatography (HPLC) with gel-permeation chromatography (GPC) along with the use of either stacked graphitized carbon and alumina solid-phase extraction (SPE) cartridges or packed Florisil®. Chromatographic separation, detection, and quantification of the pesticides from the sediment-sample extracts are done by using gas chromatography with mass spectrometry (GC/MS). Recoveries in test sediment samples fortified at 10 micrograms per kilogram (μg/kg) dry weight ranged from 75 to 102 percent; relative standard deviations ranged from 3 to 13 percent. Method detection limits (MDLs), calculated by using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), ranged from 0.6 to 3.4 μg/kg dry weight.

  11. ESTIMATION OF THERMAL PARAMETERS OF POWER BIPOLAR TRANSISTORS BY THE METHOD OF THERMAL RELAXATION DIFFERENTIAL SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    V. S. Niss

    2015-01-01

    Full Text Available Thermal performance of electronic devices determines the stability and reliability of the equipment. This leads to the need for a detailed thermal analysis of semiconductor devices. The goal of the work is evaluation of thermal parameters of high-power bipolar transistors in plastic packages TO-252 and TO-126 by a method of thermal relaxation differential spectrometry. Thermal constants of device elements and distribution structure of thermal resistance defined as discrete and continuous spectra using previously developed relaxation impedance spectrometer. Continuous spectrum, based on higher-order derivatives of the dynamic thermal impedance, follows the model of Foster, and discrete to model of Cauer. The structure of sample thermal resistance is presented in the form of siх-chain electro-thermal RC model. Analysis of the heat flow spreading in the studied structures is carried out on the basis of the concept of thermal diffusivity. For transistor structures the area and distribution of the heat flow cross-section are determined. On the basis of the measurements the thermal parameters of high-power bipolar transistors is evaluated, in particular, the structure of their thermal resistance. For all of the measured samples is obtained that the thermal resistance of the layer planting crystal makes a defining contribution to the internal thermal resistance of transistors. In the transition layer at the border of semiconductor-solder the thermal resistance increases due to changes in the mechanism of heat transfer. Defects in this area in the form of delamination of solder, voids and cracks lead to additional growth of thermal resistance caused by the reduction of the active square of the transition layer. Method of thermal relaxation differential spectrometry allows effectively control the distribution of heat flow in high-power semiconductor devices, which is important for improving the design, improve the quality of landing crystals of power

  12. Optimization of a Differential Ion Mobility Spectrometry-Tandem Mass Spectrometry Method for High-Throughput Analysis of Nicotine and Related Compounds: Application to Electronic Cigarette Refill Liquids.

    Science.gov (United States)

    Regueiro, Jorge; Giri, Anupam; Wenzl, Thomas

    2016-06-21

    Fast market penetration of electronic cigarettes is leading to an exponentially growing number of electronic refill liquids with different nicotine contents and an endless list of flavors. Therefore, rapid and simple methods allowing a fast screening of these products are necessary to detect harmful substances which can negatively impact the health of consumers. In this regard, the present work explores the capabilities of differential ion mobility spectrometry coupled to tandem mass spectrometry for high-throughput analysis of nicotine and 11 related compounds in commercial refill liquids for electronic cigarettes. The influence of main factors affecting the ion mobility separation, such as modifier types and concentration, separation voltage, and temperature, was systematically investigated. Despite small molecular weight differences among the studied compounds, a good separation was achieved in the ion mobility cell under the optimized conditions, which involved the use of ethanol as a polar gas-phase chemical modifier. Indeed, differential ion mobility was able to resolve (resolution >4) nicotine from its structural isomer anabasine without the use of any chromatographic separation. The quantitative performance of the proposed method was then evaluated, showing satisfactory precision (RSD ≤ 16%) and recoveries ranging from 85 to 100% for nicotine, and from 84 to 126% for the rest of the target analytes. Several commercial electronic cigarette refill liquids were analyzed to demonstrate the applicability of the method. In some cases, significant differences were found between labeled and measured levels of nicotine. Anatabine, cotinine, myosmine, and nornicotine were also found in some of the analyzed samples.

  13. In-situ gamma spectrometry method for determination of environmental gamma dose

    International Nuclear Information System (INIS)

    Conti, Claudio de Carvalho

    1995-07-01

    This work tries to establish a methodology for germanium detectors calibration, normally used for in situ gamma ray spectrometry, for determining the environmental exposure rate in function of the energy of the incident photons. For this purpose a computer code has been developed, based on the stripping method, for the computational spectra analysis to calculate the contribution of the partial absorption of the gamma rays (Compton effect) in the active and nonactive parts of the detector. The resulting total absorption spectrum is then converted to fluence distribution in function of the energy for the photons reaching the detector, which is then used to calculate the exposure rate or kerma in air. The unfolding and fluency convention parameters are determined by detector calibration using point gamma sources. The method is validated by comparison of the results against the calculated exposure rate at a point of interest for the standards. This method is used for the direct measurement of the exposure rate distribution in function of the energy at the site, in situ measurement technic, leading to rapid results during an emergency situation and also used for indoor measurements. (author)

  14. Peak detection method evaluation for ion mobility spectrometry by using machine learning approaches.

    Science.gov (United States)

    Hauschild, Anne-Christin; Kopczynski, Dominik; D'Addario, Marianna; Baumbach, Jörg Ingo; Rahmann, Sven; Baumbach, Jan

    2013-04-16

    Ion mobility spectrometry with pre-separation by multi-capillary columns (MCC/IMS) has become an established inexpensive, non-invasive bioanalytics technology for detecting volatile organic compounds (VOCs) with various metabolomics applications in medical research. To pave the way for this technology towards daily usage in medical practice, different steps still have to be taken. With respect to modern biomarker research, one of the most important tasks is the automatic classification of patient-specific data sets into different groups, healthy or not, for instance. Although sophisticated machine learning methods exist, an inevitable preprocessing step is reliable and robust peak detection without manual intervention. In this work we evaluate four state-of-the-art approaches for automated IMS-based peak detection: local maxima search, watershed transformation with IPHEx, region-merging with VisualNow, and peak model estimation (PME).We manually generated Metabolites 2013, 3 278 a gold standard with the aid of a domain expert (manual) and compare the performance of the four peak calling methods with respect to two distinct criteria. We first utilize established machine learning methods and systematically study their classification performance based on the four peak detectors' results. Second, we investigate the classification variance and robustness regarding perturbation and overfitting. Our main finding is that the power of the classification accuracy is almost equally good for all methods, the manually created gold standard as well as the four automatic peak finding methods. In addition, we note that all tools, manual and automatic, are similarly robust against perturbations. However, the classification performance is more robust against overfitting when using the PME as peak calling preprocessor. In summary, we conclude that all methods, though small differences exist, are largely reliable and enable a wide spectrum of real-world biomedical applications.

  15. Validation of a confirmatory method for the determination of melamine in egg by gas chromatography-mass spectrometry and ultra-performance liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Xia Xi; Ding Shuangyang; Li Xiaowei; Gong Xiao; Zhang Suxia; Jiang Haiyang; Li Jiancheng; Shen Jianzhong

    2009-01-01

    A sensitive and reliable method was developed and validated for detection and confirmation of melamine in egg based on gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Trichloroacetic acid solution was used for sample extraction and precipitation of proteins. The aqueous extracts were subjected to solid-phase extraction by mixed-mode reversed-phase/strong cation-exchange cartridges. Using ultra-performance liquid chromatography and electrospray ionization in the positive ion mode, melamine was determined by LC-MS/MS, which was completed in 5 min for each injection. For the GC-MS analysis, extracted melamine was derivatized with N,O-bis(trimethylsilyl)trifluoracetamide prior to selected ion monitoring detection in electron impact mode. The average recovery of melamine from fortified samples ranged from 85.2% to 103.2%, with coefficients of variation lower than 12%. The limit of detection obtained by GC-MS and UPLC-MS/MS was 10 and 5 μg kg -1 , respectively. This validated method was successfully applied to the determination of melamine in real samples from market.

  16. Novel method for measurement of glutathione kinetics in neonates using liquid chromatography coupled to isotope ratio mass spectrometry

    NARCIS (Netherlands)

    Schierbeek, Henk; te Braake, Frans; Godin, Jean-Philippe; Fay, Laurent-Bernard; van Goudoever, Johannes B.

    2007-01-01

    A novel analytical method using liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS) was developed for measuring the fractional synthesis rate (FSR) of glutathione (GSH) in neonates after infusion of [1-(13)C]-glycine as a tracer. After transformation of GSH into GSSG, its

  17. Nanoparticle-assisted laser desorption/ionization mass spectrometry: Novel sample preparation methods and nanoparticle screening for plant metabolite imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yagnik, Gargey B. [Iowa State Univ., Ames, IA (United States)

    2016-02-19

    The main goal of the presented research is development of nanoparticle based matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS). This dissertation includes the application of previously developed data acquisition methods, development of novel sample preparation methods, application and comparison of novel nanoparticle matrices, and comparison of two nanoparticle matrix application methods for MALDI-MS and MALDI-MS imaging.

  18. A simple gamma spectrometry method for evaluating the burnup of MTR-type HEU fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Makmal, T. [The Unit of Nuclear Engineering, Ben-Gurion University of The Negev, Beer-Sheva 84105 (Israel); Nuclear Physics and Engineering Division, Soreq Nuclear Research Center, Yavne 81800 (Israel); Aviv, O. [Radiation Safety Division, Soreq Nuclear Research Center, Yavne 81800 (Israel); Gilad, E., E-mail: gilade@bgu.ac.il [The Unit of Nuclear Engineering, Ben-Gurion University of The Negev, Beer-Sheva 84105 (Israel)

    2016-10-21

    A simple method for the evaluation of the burnup of a materials testing reactor (MTR) fuel element by gamma spectrometry is presented. The method was applied to a highly enriched uranium MTR nuclear fuel element that was irradiated in a 5 MW pool-type research reactor for a total period of 34 years. The experimental approach is based on in-situ measurements of the MTR fuel element in the reactor pool by a portable high-purity germanium detector located in a gamma cell. To corroborate the method, analytical calculations (based on the irradiation history of the fuel element) and computer simulations using a dedicated fuel cycle burnup code ORIGEN2 were performed. The burnup of the MTR fuel element was found to be 52.4±8.8%, which is in good agreement with the analytical calculations and the computer simulations. The method presented here is suitable for research reactors with either a regular or an irregular irradiation regime and for reactors with limited infrastructure and/or resources. In addition, its simplicity and the enhanced safety it confers may render this method suitable for IAEA inspectors in fuel element burnup assessments during on-site inspections. - Highlights: • Simple, inexpensive, safe and flexible experimental setup that can be quickly deployed. • Experimental results are thoroughly corroborated against ORIGEN2 burnup code. • Experimental uncertainty of 9% and 5% deviation between measurements and simulations. • Very high burnup MTR fuel element is examined, with 60% depletion of {sup 235}U. • Impact of highly irregular irradiation regime on burnup evaluation is studied.

  19. Sensitive liquid chromatography-tandem mass spectrometry method for quantification of hydrochlorothiazide in human plasma.

    Science.gov (United States)

    Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Wishu, S; Varma, D P

    2005-12-01

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of hydrochlorothiazide (I), a common diuretic and anti-hypertensive agent. The analyte and internal standard, tamsulosin (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase column (Waters symmetry C18) with a mobile phase of 10 mm ammonium acetate-methanol (15:85, v/v). The protonated analyte was quantitated in negative ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 296.1 solidus in circle 205.0 and m/z 407.2 solidus in circle 184.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-200 ng/mL for hydrochlorothiazide in human plasma. The lower limit of quantitation was 500 pg/mL, with a relative standard deviation of less than 9%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.5 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. (c) 2005 John Wiley & Sons, Ltd.

  20. Radioisotopic neutron transmission spectrometry: Quantitative analysis by using partial least-squares method

    International Nuclear Information System (INIS)

    Kim, Jong-Yun; Choi, Yong Suk; Park, Yong Joon; Jung, Sung-Hee

    2009-01-01

    Neutron spectrometry, based on the scattering of high energy fast neutrons from a radioisotope and slowing-down by the light hydrogen atoms, is a useful technique for non-destructive, quantitative measurement of hydrogen content because it has a large measuring volume, and is not affected by temperature, pressure, pH value and color. The most common choice for radioisotope neutron source is 252 Cf or 241 Am-Be. In this study, 252 Cf with a neutron flux of 6.3x10 6 n/s has been used as an attractive neutron source because of its high flux neutron and weak radioactivity. Pulse-height neutron spectra have been obtained by using in-house built radioisotopic neutron spectrometric system equipped with 3 He detector and multi-channel analyzer, including a neutron shield. As a preliminary study, polyethylene block (density of ∼0.947 g/cc and area of 40 cmx25 cm) was used for the determination of hydrogen content by using multivariate calibration models, depending on the thickness of the block. Compared with the results obtained from a simple linear calibration model, partial least-squares regression (PLSR) method offered a better performance in a quantitative data analysis. It also revealed that the PLSR method in a neutron spectrometric system can be promising in the real-time, online monitoring of the powder process to determine the content of any type of molecules containing hydrogen nuclei.

  1. A simple method for the deconvolution of 134 Cs/137 Cs peaks in gamma-ray scintillation spectrometry

    International Nuclear Information System (INIS)

    Darko, E.O.; Osae, E.K.; Schandorf, C.

    1998-01-01

    A simple method for the deconvolution of 134 Cs / 137 Cs peaks in a given mixture of 134 Cs and 137 Cs using Nal(TI) gamma-ray scintillation spectrometry is described. In this method the 795 keV energy of 134 Cs is used as a reference peak to calculate the activity of the 137 Cs directly from the measured peaks. Certified reference materials were measured using the method and compared with a high resolution gamma-ray spectrometry measurements. The results showed good agreement with the certified values. The method is very simple and does not need any complicated mathematics and computer programme to de- convolute the overlapping 604.7 keV and 661.6 keV peaks of 134 Cs and 137 Cs respectively. (author). 14 refs.; 1 tab., 2 figs

  2. Glycogenomics as a mass spectrometry-guided genome-mining method for microbial glycosylated molecules.

    Science.gov (United States)

    Kersten, Roland D; Ziemert, Nadine; Gonzalez, David J; Duggan, Brendan M; Nizet, Victor; Dorrestein, Pieter C; Moore, Bradley S

    2013-11-19

    Glycosyl groups are an essential mediator of molecular interactions in cells and on cellular surfaces. There are very few methods that directly relate sugar-containing molecules to their biosynthetic machineries. Here, we introduce glycogenomics as an experiment-guided genome-mining approach for fast characterization of glycosylated natural products (GNPs) and their biosynthetic pathways from genome-sequenced microbes by targeting glycosyl groups in microbial metabolomes. Microbial GNPs consist of aglycone and glycosyl structure groups in which the sugar unit(s) are often critical for the GNP's bioactivity, e.g., by promoting binding to a target biomolecule. GNPs are a structurally diverse class of molecules with important pharmaceutical and agrochemical applications. Herein, O- and N-glycosyl groups are characterized in their sugar monomers by tandem mass spectrometry (MS) and matched to corresponding glycosylation genes in secondary metabolic pathways by a MS-glycogenetic code. The associated aglycone biosynthetic genes of the GNP genotype then classify the natural product to further guide structure elucidation. We highlight the glycogenomic strategy by the characterization of several bioactive glycosylated molecules and their gene clusters, including the anticancer agent cinerubin B from Streptomyces sp. SPB74 and an antibiotic, arenimycin B, from Salinispora arenicola CNB-527.

  3. Technology of the Gramophone Records of the Music Museum by Fourier Transform Infrared Spectrometry (FTIR Method

    Directory of Open Access Journals (Sweden)

    Seyedeh Zeinab Afzali

    2017-02-01

    Full Text Available Music is one of the branches of the art whose helpful role and usefulness in the human’s mind and soul is undeniable. It is the only art which in the philosophers’ divisions is directly linked with the human spirit and immediate overflows the ears of his soul. The sound, as a psychological phenomenon is associated with the emotion and excitement so that sometimes calms and sometimes confuses the human. This study aims to examine the technology of the gramophone records in the Music Museum by Fourier transform infrared spectrometry (FTIR. The method of this research is experimental and the data are collected by documentation, library, and using FTIR tests. Some records of the Music Museum were studied including four samples of 78 rpm platter (stone platter, one sample of 45 rpm, and one sample of 33 rpm (vinyl platter. The results of the FTIR test indicated that the materials of the records were vinyl and shellac and in their raw material, some of the softening additives (phthalates and fillers (silica and calcium carbonate compounds had been used.

  4. A gas chromatography-mass spectrometry method for the quantitation of clobenzorex.

    Science.gov (United States)

    Cody, J T; Valtier, S

    1999-01-01

    Drugs metabolized to amphetamine or methamphetamine are potentially significant concerns in the interpretation of amphetamine-positive urine drug-testing results. One of these compounds, clobenzorex, is an anorectic drug that is available in many countries. Clobenzorex (2-chlorobenzylamphetamine) is metabolized to amphetamine by the body and excreted in the urine. Following administration, the parent compound was detectable for a shorter time than the metabolite amphetamine, which could be detected for days. Because of the potential complication posed to the interpretation of amphetamin-positive drug tests following administration of this drug, the viability of a current amphetamine procedure using liquid-liquid extraction and conversion to the heptafluorobutyryl derivative followed by gas chromatography-mass spectrometry (GC-MS) analysis was evaluated for identification and quantitation of clobenzorex. Qualitative identification of the drug was relatively straightforward. Quantitative analysis proved to be a far more challenging process. Several compounds were evaluated for use as the internal standard in this method, including methamphetamine-d11, fenfluramine, benzphetamine, and diphenylamine. Results using these compounds proved to be less than satisfactory because of poor reproducibility of the quantitative values. Because of its similar chromatographic properties to the parent drug, the compound 3-chlorobenzylamphetamine (3-Cl-clobenzorex) was evaluated in this study as the internal standard for the quantitation of clobenzorex. Precision studies showed 3-Cl-clobenzorex to produce accurate and reliable quantitative results (within-run relative standard deviations [RSDs] clobenzorex.

  5. Methods for detecting and correcting inaccurate results in inductively coupled plasma-atomic emission spectrometry

    Science.gov (United States)

    Chan, George C. Y. [Bloomington, IN; Hieftje, Gary M [Bloomington, IN

    2010-08-03

    A method for detecting and correcting inaccurate results in inductively coupled plasma-atomic emission spectrometry (ICP-AES). ICP-AES analysis is performed across a plurality of selected locations in the plasma on an unknown sample, collecting the light intensity at one or more selected wavelengths of one or more sought-for analytes, creating a first dataset. The first dataset is then calibrated with a calibration dataset creating a calibrated first dataset curve. If the calibrated first dataset curve has a variability along the location within the plasma for a selected wavelength, errors are present. Plasma-related errors are then corrected by diluting the unknown sample and performing the same ICP-AES analysis on the diluted unknown sample creating a calibrated second dataset curve (accounting for the dilution) for the one or more sought-for analytes. The cross-over point of the calibrated dataset curves yields the corrected value (free from plasma related errors) for each sought-for analyte.

  6. A robust mass spectrometry method for rapid profiling of erythrocyte ghost membrane proteomes.

    Science.gov (United States)

    Fye, Haddy K S; Mrosso, Paul; Bruce, Lesley; Thézénas, Marie-Laëtitia; Davis, Simon; Fischer, Roman; Rwegasira, Gration L; Makani, Julie; Kessler, Benedikt M

    2018-01-01

    Red blood cell (RBC) physiology is directly linked to many human disorders associated with low tissue oxygen levels or anemia including chronic obstructive pulmonary disease, congenital heart disease, sleep apnea and sickle cell anemia. Parasites such as Plasmodium spp. and phylum Apicomplexa directly target RBCs, and surface molecules within the RBC membrane are critical for pathogen interactions. Proteomics of RBC membrane 'ghost' fractions has therefore been of considerable interest, but protocols described to date are either suboptimal or too extensive to be applicable to a larger set of clinical cohorts. Here, we describe an optimised erythrocyte isolation protocol from blood, tested for various storage conditions and explored using different fractionation conditions for isolating ghost RBC membranes. Liquid chromatography mass spectrometry (LC-MS) analysis on a Q-Exactive Orbitrap instrument was used to profile proteins isolated from the comparative conditions. Data analysis was run on the MASCOT and MaxQuant platforms to assess their scope and diversity. The results obtained demonstrate a robust method for membrane enrichment enabling consistent MS based characterisation of > 900 RBC membrane proteins in single LC-MS/MS analyses. Non-detergent based membrane solubilisation methods using the tissue and supernatant fractions of isolated ghost membranes are shown to offer effective haemoglobin removal as well as diverse recovery including erythrocyte membrane proteins of high and low abundance. The methods described in this manuscript propose a medium to high throughput framework for membrane proteome profiling by LC-MS of potential applicability to larger clinical cohorts in a variety of disease contexts.

  7. High-performance liquid chromatography electrospray mass spectrometry as a method in proteomic research

    International Nuclear Information System (INIS)

    Walcher, W.

    2003-06-01

    During the sequencing of the human genome it became clear, that a lot of human diseases and/or malfunctions don't base on genomic information, but on differences at the protein level. Therefore biochemistry, biology and medicine are faced to various novel problems where new and authentic analysis methods are needed. Miniaturized chromatographic separation methods are frequently the methods of choice for the separation of peptides and proteins, when the amount of sample is limited. Monolithic capillary columns were prepared by copolymerization of styrene and divinylbenzene in the presence of a suitable porogen mixture of 1-decanol and tetrahydrofuran. The synthesized columns enabled the highly efficient separation of peptides and proteins by reversed-phase high-performance liquid chromatography (RP-HPLC) with peak capacities of 80 and more in 10 minutes. By the hyphenation of RP-HPLC to electrospray mass spectrometry (ESI-MS) the potential of the analysis method was even extended. The monolithic column technology was further miniaturized from 200 μm to 100 and 50 μm inner diameters to improve detection limits by RP-HPLC-ESI-MS. After the optimization of the RP-HPLC-ESI-MS method, the ion source and the ion transfer optics of an ion trap mass spectrometer (LCQ classic, Thermofinnigan) have been advanced for protein and peptide analysis. The improved RP-HPLC-ESI-MS system was subsequently applied to the detection of posttranslational protein modifications at the example of the nitration of bovine serum albumin (BSA). The results of the RP-HPLC-ESI-MS analysis were found to be highly reproducible, which enabled the determination of nitration degrees for different tyrosine residues in the protein sequence. Y 1 60, Y 4 96 and Y 3 52 or Y369 were found to be the predominant positions of protein nitration in BSA. At last light harvesting proteins from the photosystem II (PSII) of higher plants have been analyzed by RP-HPLC-ESI-MS and RP-HPLC-ESI-MSMS. Beside the

  8. Determination of 129I using distillation method and liquid scintillation spectrometry

    International Nuclear Information System (INIS)

    Horvathova, B.; Dulanska, S.; Remenec, B.; Matel, L.; Gardonova, V.

    2014-01-01

    The conditions for effective distillation of iodine as a screening method for the determination of 129 I by liquid scintillation spectrometry were optimized. By distillation of iodine it is possible to achieve high-purity fraction without interferences needed for measuring 129 I for liquid scintillation spectrometer. Yields of separation were determined gravimetrically using PdI 2 ·H 2 O. The environment that was found to be effective for distillation of iodine is made up of 1 - 2 mol dm -3 HNO 3 together with 0.4 g of NaNO 2 as an oxidizing agent (I . →I 2 ). For testing of distillation, suitable apparatus for distillation of iodine was designed. The apparatus was connected to a vacuum box, which sucks iodine of the distilled solution. Then the iodine was captured in a solution of NaOH at a concentration of 1.5 mol dm -3 . As part of the optimization methodology, it was found that the concentration of NaOH solution for adsorption I 2 (g) does not have any influence on the yields, as opposed to its volume, where it is necessary to use a maximum amount of NaOH in the holding flask for maximum adsorption of iodine. It was determined, that time needed for coagulation PdI 2 ·H 2 O is 24 hours and suitable time for distillation was 20 minutes. Optimized method for the determination of 129 I was applied for various matrices from NPPs in Slovak Republic. Values of 129 I for all analyzed samples were less than the minimum detectable activity (0.043 Bq). The separation yields were in the range (73.14 to 82.04)% and 129 I was measured on a liquid scintillation spectrometer TRI CARB 2900TR with high detection efficiency of 95%. (authors)

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

    International Nuclear Information System (INIS)

    Graser, Carl-Heinrich

    2015-01-01

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

  10. A novel liquid chromatography/mass spectrometry method for determination of neurotransmitters in brain tissue: Application to human tauopathies.

    Science.gov (United States)

    Forgacsova, Andrea; Galba, Jaroslav; Garruto, Ralph M; Majerova, Petra; Katina, Stanislav; Kovac, Andrej

    2018-01-15

    Neurotransmitters, small molecules widely distributed in the central nervous system are essential in transmitting electrical signals across neurons via chemical communication. Dysregulation of these chemical signaling molecules is linked to numerous neurological diseases including tauopathies. In this study, a precise and reliable liquid chromatography method was established with tandem mass spectrometry detection for the simultaneous determination of aspartic acid, asparagine, glutamic acid, glutamine, γ-aminobutyric acid, N-acetyl-l-aspartic acid, pyroglutamic acid, acetylcholine and choline in human brain tissue. The method was successfully applied to the analysis of human brain tissues from three different tauopathies; corticobasal degeneration, progressive supranuclear palsy and parkinsonism-dementia complex of Guam. Neurotransmitters were analyzed on ultra-high performance chromatography (UHPLC) using an ethylene bridged hybrid amide column coupled with tandem mass spectrometry (MS/MS). Identification and quantification of neurotransmitters was carried out by ESI+ mass spectrometry detection. We optimized sample preparation to achieve simple and fast extraction of all nine analytes. Our method exhibited an excellent linearity for all analytes (all coefficients of determination >0.99), with inter-day and intra-day precision yielding relative standard deviations 3.2%-11.2% and an accuracy was in range of 92.6%-104.3%. The present study, using the above method, is the first to demonstrate significant alterations of brain neurotransmitters caused by pathological processes in the brain tissues of patient with three different tauopathies. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Automated Fast Screening Method for Cocaine Identification in Seized Drug Samples Using a Portable Fourier Transform Infrared (FT-IR) Instrument.

    Science.gov (United States)

    Mainali, Dipak; Seelenbinder, John

    2016-05-01

    Quick and presumptive identification of seized drug samples without destroying evidence is necessary for law enforcement officials to control the trafficking and abuse of drugs. This work reports an automated screening method to detect the presence of cocaine in seized samples using portable Fourier transform infrared (FT-IR) spectrometers. The method is based on the identification of well-defined characteristic vibrational frequencies related to the functional group of the cocaine molecule and is fully automated through the use of an expert system. Traditionally, analysts look for key functional group bands in the infrared spectra and characterization of the molecules present is dependent on user interpretation. This implies the need for user expertise, especially in samples that likely are mixtures. As such, this approach is biased and also not suitable for non-experts. The method proposed in this work uses the well-established "center of gravity" peak picking mathematical algorithm and combines it with the conditional reporting feature in MicroLab software to provide an automated method that can be successfully employed by users with varied experience levels. The method reports the confidence level of cocaine present only when a certain number of cocaine related peaks are identified by the automated method. Unlike library search and chemometric methods that are dependent on the library database or the training set samples used to build the calibration model, the proposed method is relatively independent of adulterants and diluents present in the seized mixture. This automated method in combination with a portable FT-IR spectrometer provides law enforcement officials, criminal investigators, or forensic experts a quick field-based prescreening capability for the presence of cocaine in seized drug samples. © The Author(s) 2016.

  12. A calibration method for the measurement of IR detector spectral responses using a FTIR spectrometer equipped with a DTGS reference cell

    Science.gov (United States)

    Gravrand, Olivier; Wlassow, J.; Bonnefond, L.

    2014-07-01

    Various high performance IR detectors are today available on the market from QWIPs to narrow gap semiconductor photodiodes, which exhibit various spectral features. In the astrophysics community, the knowledge of the detector spectral shape is of first importance. This quantity (spectral QE or response) is usually measured by means of a monochromator followed by an integrating sphere and compared to a calibrated reference detector. This approach is usually very efficient in the visible range, where all optical elements are very well known, particularly the reference detector. This setup is also widely used in the near IR (up to 3μm) but as the wavelength increases, it becomes less efficient. For instance, the internal emittance of integrating spheres in the IR, and the bad knowledge of reference detectors for longer wavelengths tend to degrade the measurement reliability. Another approach may therefore be considered, using a Fourier transform IR spectrometer (FTIR). In this case, as opposed to the monochromator, the tested detector is not in low flux condition, the incident light containing a mix of different wavelengths. Therefore, the reference detector has to be to be sensitive (and known) in the whole spectral band of interest, because it will sense all those wavelengths at the same time. A popular detector used in this case is a Deuterated Triglycine Sulfate thermal detector (DTGS). Being a pyro detetector, the spectral response of such a detector is very flat, mainly limited by its window. However, the response of such a detector is very slow, highly depending on the temporal frequency of the input signal. Moreover, being a differential detector, it doesn't work in DC. In commercial FTIR spectrometers, the source luminance is usually continuously modulated by the moving interferometer, and the result is that the interferogram mixes optical spectral information (optical path difference) and temporal variations (temporal frequency) so that the temporal

  13. Burn-up determination of irradiated uranium oxide by means of direct gama spectrometry and by radiochemical method

    International Nuclear Information System (INIS)

    Cunha, I.I.L.; Nastasi, M.J.C.; Lima, F.W.

    1981-09-01

    The burn-up of thermal neutrons irradiated U 3 O 8 (natural uranium) samples has been determined by using both direct gamma spectrometry and radiochemical methods and the results obtained were compared. The fission products 144 Ce, 103 Ru, 106 Ru, 137 Cs and 95 Zr were chosen as burn-up monitors. In order to isolate the radioisotopes chosen as monitors, a radiochemical separation procedure has been established, in which the solvent extraction technique was used to separate cerium, cesium and ruthenium one from the other and all of them from uranium. The separation between zirconium and niobium and of both elements from the other radioisotopes and uranium was accomplished by means of adsorption on a silica-gel column, followed by selective elution of zirconium and of niobium. When use was made of the direct gamma-ray spectrometry method, the radioactivity of each nuclide of interest was measured in presence of all others. For this purpose use was made of gamma-ray spectrometry and of a Ge-Li detector. Comparison of burn-up values obtained by both methods was made by means of Student's 't' test, and this showed that results obtained in each case are statistically equal. (Author) [pt

  14. A novel frequency analysis method for assessing K(ir)2.1 and Na (v)1.5 currents.

    Science.gov (United States)

    Rigby, J R; Poelzing, S

    2012-04-01

    Voltage clamping is an important tool for measuring individual currents from an electrically active cell. However, it is difficult to isolate individual currents without pharmacological or voltage inhibition. Herein, we present a technique that involves inserting a noise function into a standard voltage step protocol, which allows one to characterize the unique frequency response of an ion channel at different step potentials. Specifically, we compute the fast Fourier transform for a family of current traces at different step potentials for the inward rectifying potassium channel, K(ir)2.1, and the channel encoding the cardiac fast sodium current, Na(v)1.5. Each individual frequency magnitude, as a function of voltage step, is correlated to the peak current produced by each channel. The correlation coefficient vs. frequency relationship reveals that these two channels are associated with some unique frequencies with high absolute correlation. The individual IV relationship can then be recreated using only the unique frequencies with magnitudes of high absolute correlation. Thus, this study demonstrates that ion channels may exhibit unique frequency responses.

  15. Gold finger formation studied by high-resolution mass spectrometry and in silico methods

    NARCIS (Netherlands)

    Laskay, Ü.A.; Garino, C.; Tsybin, Y.O.; Salassa, L.; Casini, A.

    2015-01-01

    High-resolution mass spectrometry and quantum mechanics/molecular mechanics studies were employed for characterizing the formation of two gold finger (GF) domains from the reaction of zinc fingers (ZF) with gold complexes. The influence of both the gold oxidation state and the ZF coordination sphere

  16. FT-IR spectra of the anti-HIV nucleoside analogue d4T (Stavudine). Solid state simulation by DFT methods and scaling by different procedures

    Science.gov (United States)

    Alcolea Palafox, M.; Kattan, D.; Afseth, N. K.

    2018-04-01

    A theoretical and experimental vibrational study of the anti-HIV d4T (stavudine or Zerit) nucleoside analogue was carried out. The predicted spectra in the three most stable conformers in the biological active anti-form of the isolated state were compared. Comparison of the conformers with those of the natural nucleoside thymidine was carried out. The calculated spectra were scaled by using different scaling procedures and three DFT methods. The TLSE procedure leads to the lowest error and is thus recommended for scaling. With the population of these conformers the IR gas-phase spectra were predicted. The crystal unit cell of the different polymorphism forms of d4T were simulated through dimer forms by using DFT methods. The scaled spectra of these dimer forms were compared. The FT-IR spectrum was recorded in the solid state in the 400-4000 cm-1 range. The respective vibrational bands were analyzed and assigned to different normal modes of vibration by comparison with the scaled vibrational values of the different dimer forms. Through this comparison, the polymorphous form of the solid state sample was identified. The study indicates that d4T exist only in the ketonic form in the solid state. The results obtained were in agreement with those determined in related anti-HIV nucleoside analogues.

  17. Determination of Au, Ir, Os, Pd, Pt, Ru in high-purity metals by neutron activation

    International Nuclear Information System (INIS)

    Samadi, A.A.; Fedoroff, M.

    1978-01-01

    This determination was achieved by thermal neutron activation, chemical separations and radioactivity measurements by γ spectrometry. In order to develop chemical separations, some studies on the distillation and ion exchange of platinum group elements were perfomed. The fixation of these elements on an anion exchange resin in a nitrite medium was studied more particularly. This method enables a fully quantitative fixation. The detection limits in these irradiation conditions ranges from 10 -12 g for Ir to 10 -8 g for Pd [fr

  18. Statistical signal processing for gamma spectrometry: application for a pileup correction method

    International Nuclear Information System (INIS)

    Trigano, T.

    2005-12-01

    The main objective of gamma spectrometry is to characterize the radioactive elements of an unknown source by studying the energy of the emitted photons. When a photon interacts with a detector, its energy is converted into an electrical pulse. The histogram obtained by collecting the energies can be used to identify radioactive elements and measure their activity. However, at high counting rates, perturbations which are due to the stochastic aspect of the temporal signal can cripple the identification of the radioactive elements. More specifically, since the detector has a finite resolution, close arrival times of photons which can be modeled as an homogeneous Poisson process cause pile-ups of individual pulses. This phenomenon distorts energy spectra by introducing multiple fake spikes and prolonging artificially the Compton continuum, which can mask spikes of low intensity. The objective of this thesis is to correct the distortion caused by the pile-up phenomenon in the energy spectra. Since the shape of photonic pulses depends on many physical parameters, we consider this problem in a nonparametric framework. By introducing an adapted model based on two marked point processes, we establish a nonlinear relation between the probability measure associated to the observations and the probability density function we wish to estimate. This relation is derived both for continuous and for discrete time signals, and therefore can be used on a large set of detectors and from an analog or digital point of view. It also provides a framework to this problem, which can be considered as a problem of nonlinear density deconvolution and nonparametric density estimation from indirect measurements. Using these considerations, we propose an estimator obtained by direct inversion. We show that this estimator is consistent and almost achieves the usual rate of convergence obtained in classical nonparametric density estimation in the L 2 sense. We have applied our method to a set of

  19. Effect of Gold Nanoparticles on Prostate Dose Distribution under Ir-192 Internal and 18 MV External Radiotherapy Procedures Using Gel Dosimetry and Monte Carlo Method

    Directory of Open Access Journals (Sweden)

    Khosravi H.

    2015-03-01

    Full Text Available Background: Gel polymers are considered as new dosimeters for determining radiotherapy dose distribution in three dimensions. Objective: The ability of a new formulation of MAGIC-f polymer gel was assessed by experimental measurement and Monte Carlo (MC method for studying the effect of gold nanoparticles (GNPs in prostate dose distributions under the internal Ir-192 and external 18MV radiotherapy practices. Method: A Plexiglas phantom was made representing human pelvis. The GNP shaving 15 nm in diameter and 0.1 mM concentration were synthesized using chemical reduction method. Then, a new formulation of MAGIC-f gel was synthesized. The fabricated gel was poured in the tubes located at the prostate (with and without the GNPs and bladder locations of the phantom. The phantom was irradiated to an Ir-192 source and 18 MV beam of a Varian linac separately based on common radiotherapy procedures used for prostate cancer. After 24 hours, the irradiated gels were read using a Siemens 1.5 Tesla MRI scanner. The absolute doses at the reference points and isodose curves resulted from the experimental measurement of the gels and MC simulations following the internal and external radiotherapy practices were compared. Results: The mean absorbed doses measured with the gel in the presence of the GNPs in prostate were 15% and 8 % higher than the corresponding values without the GNPs under the internal and external radiation therapies, respectively. MC simulations also indicated a dose increase of 14 % and 7 % due to presence of the GNPs, for the same experimental internal and external radiotherapy practices, respectively. Conclusion: There was a good agreement between the dose enhancement factors (DEFs estimated with MC simulations and experiment gel measurements due to the GNPs. The results indicated that the polymer gel dosimetry method as developed and used in this study, can be recommended as a reliable method for investigating the DEF of GNPs in internal

  20. The energy calibration and precision of a gamma spectrometry unit - Method using the electron annihilation energy as the only standard

    International Nuclear Information System (INIS)

    Hoclet, Michel

    1971-06-01

    Spectrometry using Ge(Li) detectors is discussed. The excellent resolution of this type of detector, the mathematical analysis of the spectral lines of the pulses, and the reproducibility of the spectrometer enable highly accurate measurements of the abscises (some 10 -5 ) corresponding to the peaks. A method using the annihilation energy of the electron as the only standard was developed. The method is applied to the measurement of the gamma ray energies of the radioelements: 22 Na, 24 Na, 56 Mn, 56 Co, 59 Fe, 72 Ga, 88 Y, 122 Sb, 124 Sb and 137 Cs. (author) [fr

  1. Atomic spectrometry methods for wine analysis: A critical evaluation and discussion of recent applications

    Energy Technology Data Exchange (ETDEWEB)

    Grindlay, Guillermo, E-mail: guillermo.grindlay@ua.es [Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 Alicante (Spain); Mora, Juan; Gras, Luis [Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 Alicante (Spain); Loos-Vollebregt, Margaretha T.C. de [Delft University of Technology, Faculty of Applied Sciences, Analytical Biotechnology, Julianalaan 67, 2628 BC Delft (Netherlands)

    2011-04-08

    The analysis of wine is of great importance since wine components strongly determine its stability, organoleptic or nutrition characteristics. In addition, wine analysis is also important to prevent fraud and to assess toxicological issues. Among the different analytical techniques described in the literature, atomic spectrometry has been traditionally employed for elemental wine analysis due to its simplicity and good analytical figures of merit. The scope of this review is to summarize the main advantages and drawbacks of various atomic spectrometry techniques for elemental wine analysis. Special attention is paid to interferences (i.e. matrix effects) affecting the analysis as well as the strategies available to mitigate them. Finally, latest studies about wine speciation are briefly discussed.

  2. Atomic spectrometry methods for wine analysis: a critical evaluation and discussion of recent applications.

    Science.gov (United States)

    Grindlay, Guillermo; Mora, Juan; Gras, Luis; de Loos-Vollebregt, Margaretha T C

    2011-04-08

    The analysis of wine is of great importance since wine components strongly determine its stability, organoleptic or nutrition characteristics. In addition, wine analysis is also important to prevent fraud and to assess toxicological issues. Among the different analytical techniques described in the literature, atomic spectrometry has been traditionally employed for elemental wine analysis due to its simplicity and good analytical figures of merit. The scope of this review is to summarize the main advantages and drawbacks of various atomic spectrometry techniques for elemental wine analysis. Special attention is paid to interferences (i.e. matrix effects) affecting the analysis as well as the strategies available to mitigate them. Finally, latest studies about wine speciation are briefly discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Atomic spectrometry methods for wine analysis: A critical evaluation and discussion of recent applications

    International Nuclear Information System (INIS)

    Grindlay, Guillermo; Mora, Juan; Gras, Luis; Loos-Vollebregt, Margaretha T.C. de

    2011-01-01

    The analysis of wine is of great importance since wine components strongly determine its stability, organoleptic or nutrition characteristics. In addition, wine analysis is also important to prevent fraud and to assess toxicological issues. Among the different analytical techniques described in the literature, atomic spectrometry has been traditionally employed for elemental wine analysis due to its simplicity and good analytical figures of merit. The scope of this review is to summarize the main advantages and drawbacks of various atomic spectrometry techniques for elemental wine analysis. Special attention is paid to interferences (i.e. matrix effects) affecting the analysis as well as the strategies available to mitigate them. Finally, latest studies about wine speciation are briefly discussed.

  4. irGPU.proton.Net: Irregular strong charge interaction networks of protonatable groups in protein molecules--a GPU solver using the fast multipole method and statistical thermodynamics.

    Science.gov (United States)

    Kantardjiev, Alexander A

    2015-04-05

    A cluster of strongly interacting ionization groups in protein molecules with irregular ionization behavior is suggestive for specific structure-function relationship. However, their computational treatment is unconventional (e.g., lack of convergence in naive self-consistent iterative algorithm). The stringent evaluation requires evaluation of Boltzmann averaged statistical mechanics sums and electrostatic energy estimation for each microstate. irGPU: Irregular strong interactions in proteins--a GPU solver is novel solution to a versatile problem in protein biophysics--atypical protonation behavior of coupled groups. The computational severity of the problem is alleviated by parallelization (via GPU kernels) which is applied for the electrostatic interaction evaluation (including explicit electrostatics via the fast multipole method) as well as statistical mechanics sums (partition function) estimation. Special attention is given to the ease of the service and encapsulation of theoretical details without sacrificing rigor of computational procedures. irGPU is not just a solution-in-principle but a promising practical application with potential to entice community into deeper understanding of principles governing biomolecule mechanisms. © 2015 Wiley Periodicals, Inc.

  5. Vibrational spectra (FT-IR, FT-Raman), frontier molecular orbital, first hyperpolarizability, NBO analysis and thermodynamics properties of Piroxicam by HF and DFT methods

    Science.gov (United States)

    Suresh, S.; Gunasekaran, S.; Srinivasan, S.

    2015-03-01

    The solid phase FT-IR and FT-Raman spectra of 4-Hydroxy-2-methyl-N-(2-pyridinyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (Piroxicam) have been recorded in the region 4000-400 and 4000-100 cm-1 respectively. The molecular geometry, harmonic vibrational frequencies and bonding features of piroxicam in the ground state have been calculated by Hartree-Fock (HF) and density functional theory (DFT) methods using 6-311++G(d,p) basis set. The calculated harmonic vibrational frequencies are scaled and they are compared with experimental obtained by FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of the title compound has been made on the basis of the calculated potential energy distribution (PED). The electronic properties, such as HOMO and LUMO energies, molecular electrostatic potential (MESP) are also performed. The linear polarizability (α) and the first order hyper polarizability (β) values of the title compound have been computed. The molecular stability arising from hyper conjugative interaction, charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  6. Effect of Gold Nanoparticles on Prostate Dose Distribution under Ir-192 Internal and 18 MV External Radiotherapy Procedures Using Gel Dosimetry and Monte Carlo Method.

    Science.gov (United States)

    Khosravi, H; Hashemi, B; Mahdavi, S R; Hejazi, P

    2015-03-01

    Gel polymers are considered as new dosimeters for determining radiotherapy dose distribution in three dimensions. The ability of a new formulation of MAGIC-f polymer gel was assessed by experimental measurement and Monte Carlo (MC) method for studying the effect of gold nanoparticles (GNPs) in prostate dose distributions under the internal Ir-192 and external 18MV radiotherapy practices. A Plexiglas phantom was made representing human pelvis. The GNP shaving 15 nm in diameter and 0.1 mM concentration were synthesized using chemical reduction method. Then, a new formulation of MAGIC-f gel was synthesized. The fabricated gel was poured in the tubes located at the prostate (with and without the GNPs) and bladder locations of the phantom. The phantom was irradiated to an Ir-192 source and 18 MV beam of a Varian linac separately based on common radiotherapy procedures used for prostate cancer. After 24 hours, the irradiated gels were read using a Siemens 1.5 Tesla MRI scanner. The absolute doses at the reference points and isodose curves resulted from the experimental measurement of the gels and MC simulations following the internal and external radiotherapy practices were compared. The mean absorbed doses measured with the gel in the presence of the GNPs in prostate were 15% and 8 % higher than the corresponding values without the GNPs under the internal and external radiation therapies, respectively. MC simulations also indicated a dose increase of 14 % and 7 % due to presence of the GNPs, for the same experimental internal and external radiotherapy practices, respectively. There was a good agreement between the dose enhancement factors (DEFs) estimated with MC simulations and experiment gel measurements due to the GNPs. The results indicated that the polymer gel dosimetry method as developed and used in this study, can be recommended as a reliable method for investigating the DEF of GNPs in internal and external radiotherapy practices.

  7. TPD IR studies of CO desorption from zeolites CuY and CuX

    Science.gov (United States)

    Datka, Jerzy; Kozyra, Paweł

    2005-06-01

    The desorption of CO from zeolites CuY and CuX was followed by TPD-IR method. This is a combination of temperature programmed desorption and IR spectroscopy. In this method, the status of activated zeolite (before adsorption), the process of adsorption, and the status of adsorbed molecules can be followed by IR spectroscopy, and the process of desorption (with linear temperature increase) can be followed both by IR spectroscopy and by mass spectrometry. IR spectra have shown two kinds of Cu + sites in both CuY and CuX. Low frequency (l.f.) band (2140 cm -1 in CuY and 2130 cm -1 in CuX) of adsorbed CO represents Cu + sites for which π back donation is stronger and σ donation is weaker whereas high frequency h.f. band (2160 cm -1 in CuY and 2155 cm -1 in CuX) represent Cu + sites for which π back donation is weaker and σ donation is stronger. The TPD-IR experiments evidenced that the Cu + sites represented by l.f. band bond CO more weakly than those represented by h.f. one, indicating that σ donation has more important impact to the strength of Cu +-CO bonding. On the contrary, π back donation has bigger contribution to the activation of adsorbed molecules.

  8. International comparison of methods to test the validity of dead-time and pile-up corrections for high-precision. gamma. -ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Houtermans, H.; Schaerf, K.; Reichel, F. (International Atomic Energy Agency, Vienna (Austria)); Debertin, K. (Physikalisch-Technische Bundesanstalt, Braunschweig (Germany, F.R.))

    1983-02-01

    The International Atomic Energy Agency organized an international comparison of methods applied in high-precision ..gamma..-ray spectrometry for the correction of dead-time and pile-up losses. Results of this comparison are reported and discussed.

  9. METHOD 332.0: DETERMINATION OF PERCHLORATE IN DRINKING WATER BY ION CHROMATOGRAPHY WITH SUPPRESSED CONDUCTIVITY AND ELECTROSPRAY IONIZATION MASS SPECTROMETRY

    Science.gov (United States)

    This method is applicable to the identification and quantitation of perchlorate in raw and finished drinking waters. The approach used is ion chromatography with suppressed conductivity and electrospray ionization mass spectrometry (IC-ESI/MS)

  10. EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

    Science.gov (United States)

    Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

  11. Spectral-ratio radon background correction method in airborne γ-ray spectrometry based on compton scattering deduction

    International Nuclear Information System (INIS)

    Gu Yi; Xiong Shengqing; Zhou Jianxin; Fan Zhengguo; Ge Liangquan

    2014-01-01

    γ-ray released by the radon daughter has severe impact on airborne γ-ray spectrometry. The spectral-ratio method is one of the best mathematical methods for radon background deduction in airborne γ-ray spectrometry. In this paper, an advanced spectral-ratio method was proposed which deducts Compton scattering ray by the fast Fourier transform rather than tripping ratios, the relationship between survey height and correction coefficient of the advanced spectral-ratio radon background correction method was studied, the advanced spectral-ratio radon background correction mathematic model was established, and the ground saturation model calibrating technology for correction coefficient was proposed. As for the advanced spectral-ratio radon background correction method, its applicability and correction efficiency are improved, and the application cost is saved. Furthermore, it can prevent the physical meaning lost and avoid the possible errors caused by matrix computation and mathematical fitting based on spectrum shape which is applied in traditional correction coefficient. (authors)

  12. MERCURY QUANTIFICATION IN SOILS USING THERMAL DESORPTION AND ATOMIC ABSORPTION SPECTROMETRY: PROPOSAL FOR AN ALTERNATIVE METHOD OF ANALYSIS

    Directory of Open Access Journals (Sweden)

    Liliane Catone Soares

    2015-08-01

    Full Text Available Despite the considerable environmental importance of mercury (Hg, given its high toxicity and ability to contaminate large areas via atmospheric deposition, little is known about its activity in soils, especially tropical soils, in comparison with other heavy metals. This lack of information about Hg arises because analytical methods for determination of Hg are more laborious and expensive compared to methods for other heavy metals. The situation is even more precarious regarding speciation of Hg in soils since sequential extraction methods are also inefficient for this metal. The aim of this paper is to present a technique of thermal desorption associated with atomic absorption spectrometry, TDAAS, as an efficient tool for quantitative determination of Hg in soils. The method consists of the release of Hg by heating, followed by its quantification by atomic absorption spectrometry. It was developed by constructing calibration curves in different soil samples based on increasing volumes of standard Hg2+ solutions. Performance, accuracy, precision, and quantification and detection limit parameters were evaluated. No matrix interference was detected. Certified reference samples and comparison with a Direct Mercury Analyzer, DMA (another highly recognized technique, were used in validation of the method, which proved to be accurate and precise.

  13. Method Development for Rapid Analysis of Natural Radioactive Nuclides Using Sector Field Inductively Coupled Plasma Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lim, J.M.; Ji, Y.Y.; Lee, H.; Park, J.H.; Jang, M.; Chung, K.H.; Kang, M.J.; Choi, G.S. [Korea Atomic Energy Research Institute (Korea, Republic of)

    2014-07-01

    As an attempt to reduce the social costs and apprehension arising from radioactivity in the environment, an accurate and rapid assessment of radioactivity is highly desirable. Naturally occurring radioactive materials (NORM) are widely spread throughout the environment. The concern with radioactivity from these materials has therefore been growing for the last decade. In particular, radiation exposure in the industry when handling raw materials (e.g., coal mining and combustion, oil and gas production, metal mining and smelting, mineral sands (REE, Ti, Zr), fertilizer (phosphate), and building materials) has been brought to the public's attention. To decide the proper handling options, a rapid and accurate analytical method that can be used to evaluate the radioactivity of radionuclides (e.g., {sup 238}U, {sup 235}U, {sup 232}Th, {sup 226}Ra, and {sup 40}K) should be developed and validated. Direct measuring methods such as alpha spectrometry, a liquid scintillation counter (LSC), and mass-spectrometry are usually used for the measurement of radioactivity in NORM samples, and they encounter the most significant difficulties during pretreatment (e.g., purification, speciation, and dilution/enrichment). Since the pretreatment process consequently plays an important role in the measurement uncertainty, method development and validation should be performed. Furthermore, a-spectrometry has a major disadvantage of a long counting time, while it has a prominent measurement capability at a very low activity level of {sup 238}U, {sup 235}U, {sup 232}Th, and {sup 226}Ra. Contrary to the α-spectrometry method, a measurement technique using ICP-MS allow radioactivity in many samples to be measured in a short time period with a high degree of accuracy and precision. In this study, a method was developed for a rapid analysis of natural radioactive nuclides using ICP-MS. A sample digestion process was established using LiBO{sub 2} fusion and Fe co-precipitation. A magnetic

  14. Accuracy of some routine method used in clinical chemistry as judged by isotope dilution-mass spectrometry

    International Nuclear Information System (INIS)

    Bjoerkhem, I.; Bergman, A.; Falk, O.; Kallner, A.; Lantto, O.; Svensson, L.; Akerloef, E.; Blomstrand, R.

    1981-01-01

    Serum from patients was pooled, filtered, dispensed, and frozen. This pooled specimen was used for accuracy control in 64 participating laboratories in Sweden. Mean values (state-of-the-art values) were obtained for creatinine, cholesterol, glucose, urea, uric acid, and cortisol. These values were compared with values obtained with highly accurate reference methods based on isotope dilution-mass spectrometry. Differences were marked in the case of determination of creatinine and cortisol. Concerning the other components, the differences between the state-of-the-art value and the values obtained with the reference methods were negligible. Moreover, the glucose oxidase and the oxime methods for determination of glucose and urea were found to give significantly lower values than the hexokinase and urease methods, respectively. Researchers conclude that methods with a higher degree of accuracy are required for routine determination of creatinine and cortisol

  15. Formic acid hydrolysis/liquid chromatography isotope dilution mass spectrometry: An accurate method for large DNA quantification.

    Science.gov (United States)

    Shibayama, Sachie; Fujii, Shin-Ichiro; Inagaki, Kazumi; Yamazaki, Taichi; Takatsu, Akiko

    2016-10-14

    Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) with formic acid hydrolysis was established for the accurate quantification of λDNA. The over-decomposition of nucleobases in formic acid hydrolysis was restricted by optimizing the reaction temperature and the reaction time, and accurately corrected by using deoxynucleotides (dNMPs) and isotope-labeled dNMPs as the calibrator and the internal standard, respectively. The present method could quantify λDNA with an expanded uncertainty of 4.6% using 10fmol of λDNA. The analytical results obtained with the present method were validated by comparing with the results of phosphate-base quantification by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed good agreement with each other. We conclude that the formic acid hydrolysis/LC-IDMS method can quantify λDNA accurately and is promising as the primary method for the certification of DNA as reference material. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Estimation and Mapping Forest Attributes Using “k Nearest Neighbor” Method on IRS-P6 LISS III Satellite Image Data

    Directory of Open Access Journals (Sweden)

    Amir Eslam Bonyad

    2015-06-01

    Full Text Available In this study, we explored the utility of k Nearest Neighbor (kNN algorithm to integrate IRS-P6 LISS III satellite imagery data and ground inventory data for application in forest attributes (DBH, trees height, volume, basal area, density and forest cover type estimation and mapping. The ground inventory data was based on a systematic-random sampling grid and the numbers of sampling plots were 408 circular plots in a plantation in Guilan province, north of Iran. We concluded that kNN method was useful tool for mapping at a fine accuracy between 80% and 93.94%. Values of k between 5 and 8 seemed appropriate. The best distance metrics were found Euclidean, Fuzzy and Mahalanobis. Results showed that kNN was accurate enough for practical applicability for mapping forest areas.

  17. Error analysis of isotope dilution mass spectrometry method with internal standard

    International Nuclear Information System (INIS)

    Rizhinskii, M.W.; Vitinskii, M.Y.

    1989-02-01

    The computation algorithms of the normalized isotopic ratios and element concentration by isotope dilution mass spectrometry with internal standard are presented. A procedure based on the Monte-Carlo calculation is proposed for predicting the magnitude of the errors to be expected. The estimation of systematic and random errors is carried out in the case of the certification of uranium and plutonium reference materials as well as for the use of those reference materials in the analysis of irradiated nuclear fuels. 4 refs, 11 figs, 2 tabs

  18. On the Importance of Mathematical Methods for Analysis of MALDI-Imaging Mass Spectrometry Data

    Directory of Open Access Journals (Sweden)

    Trede Dennis

    2012-03-01

    Full Text Available In the last decade, matrix-assisted laser desorption/ionization (MALDI imaging mass spectrometry (IMS, also called as MALDI-imaging, has proven its potential in proteomics and was successfully applied to various types of biomedical problems, in particular to histopathological label-free analysis of tissue sections. In histopathology, MALDI-imaging is used as a general analytic tool revealing the functional proteomic structure of tissue sections, and as a discovery tool for detecting new biomarkers discriminating a region annotated by an experienced histologist, in particular, for cancer studies.

  19. Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications

    OpenAIRE

    Bhaskar, V. Vijaya; Middha, Anil; Srivastava, Pratima; Rajagopal, Sriram

    2015-01-01

    A rapid, sensitive and selective pseudoMRM (pMRM)-based method for the determination of solutol HS15 (SHS15) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LCâMS/MS). The most abundant ions corresponding to SHS15 free polyethyleneglycol (PEG) oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for pMRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using ...

  20. Reactor gamma spectrometry: status

    International Nuclear Information System (INIS)

    Gold, R.; Kaiser, B.J.

    1979-01-01

    Current work is described for Compton Recoil Gamma-Ray Spectrometry including developments in experimental technique as well as recent reactor spectrometry measurements. The current status of the method is described concerning gamma spectromoetry probe design and response characteristics. Emphasis is given to gamma spectrometry work in US LWR and BR programs. Gamma spectrometry in BR environments are outlined by focussing on start-up plans for the Fast Test Reactor (FTR). Gamma spectrometry results are presented for a LWR pressure vessel mockup in the Poolside Critical Assembly (PCA) at Oak Ridge National Laboratory

  1. Classification-based comparison of pre-processing methods for interpretation of mass spectrometry generated clinical datasets

    Directory of Open Access Journals (Sweden)

    Hoefsloot Huub CJ

    2009-05-01

    Full Text Available Abstract Background Mass spectrometry is increasingly being used to discover proteins or protein profiles associated with disease. Experimental design of mass-spectrometry studies has come under close scrutiny and the importance of strict protocols for sample collection is now understood. However, the question of how best to process the large quantities of data generated is still unanswered. Main challenges for the analysis are the choice of proper pre-processing and classification methods. While these two issues have been investigated in isolation, we propose to use the classification of patient samples as a clinically relevant benchmark for the evaluation of pre-processing methods. Results Two in-house generated clinical SELDI-TOF MS datasets are used in this study as an example of high throughput mass-spectrometry data. We perform a systematic comparison of two commonly used pre-processing methods as implemented in Ciphergen ProteinChip Software and in the Cromwell package. With respect to reproducibility, Ciphergen and Cromwell pre-processing are largely comparable. We find that the overlap between peaks detected by either Ciphergen ProteinChip Software or Cromwell is large. This is especially the case for the more stringent peak detection settings. Moreover, similarity of the estimated intensities between matched peaks is high. We evaluate the pre-processing methods using five different classification methods. Classification is done in a double cross-validation protocol using repeated random sampling to obtain an unbiased estimate of classification accuracy. No pre-processing method significantly outperforms the other for all peak detection settings evaluated. Conclusion We use classification of patient samples as a clinically relevant benchmark for the evaluation of pre-processing methods. Both pre-processing methods lead to similar classification results on an ovarian cancer and a Gaucher disease dataset. However, the settings for pre

  2. InSourcerer: a high-throughput method to search for unknown metabolite modifications by mass spectrometry.

    Science.gov (United States)

    Mrzic, Aida; Lermyte, Frederik; Vu, Trung Nghia; Valkenborg, Dirk; Laukens, Kris

    2017-09-15

    Using mass spectrometry, the analysis of known metabolite structures has become feasible in a systematic high-throughput fashion. Nevertheless, the identification of previously unknown structures remains challenging, partially because many unidentified variants originate from known molecules that underwent unexpected modifications. Here, we present a method for the discovery of unknown metabolite modifications and conjugate metabolite isoforms in a high-throughput fashion. The method is based on user-controlled in-source fragmentation which is used to induce loss of weakly bound modifications. This is followed by the comparison of product ions from in-source fragmentation and collision-induced dissociation (CID). Diagonal MS 2 -MS 3 matching allows the detection of unknown metabolite modifications, as well as substructure similarities. As the method relies heavily on the advantages of in-source fragmentation and its ability to 'magically' elucidate unknown modification, we have named it inSourcerer as a portmanteau of in-source and sorcerer. The method was evaluated using a set of 15 different cytokinin standards. Product ions from in-source fragmentation and CID were compared. Hierarchical clustering revealed that good matches are due to the presence of common substructures. Plant leaf extract, spiked with a mix of all 15 standards, was used to demonstrate the method's ability to detect these standards in a complex mixture, as well as confidently identify compounds already present in the plant material. Here we present a method that incorporates a classic liquid chromatography/mass spectrometry (LC/MS) workflow with fragmentation models and computational algorithms. The assumptions upon which the concept of the method was built were shown to be valid and the method showed that in-source fragmentation can be used to pinpoint structural similarities and indicate the occurrence of a modification. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Mass Spectrometry-Based Methods for Identifying Oxidized Proteins in Disease: Advances and Challenges

    Directory of Open Access Journals (Sweden)

    Ivan Verrastro

    2015-04-01

    Full Text Available Many inflammatory diseases have an oxidative aetiology, which leads to oxidative damage to biomolecules, including proteins. It is now increasingly recognized that oxidative post-translational modifications (oxPTMs of proteins affect cell signalling and behaviour, and can contribute to pathology. Moreover, oxidized proteins have potential as biomarkers for inflammatory diseases. Although many assays for generic protein oxidation and breakdown products of protein oxidation are available, only advanced tandem mass spectrometry approaches have the power to localize specific oxPTMs in identified proteins. While much work has been carried out using untargeted or discovery mass spectrometry approaches, identification of oxPTMs in disease has benefitted from the development of sophisticated targeted or semi-targeted scanning routines, combined with chemical labeling and enrichment approaches. Nevertheless, many potential pitfalls exist which can result in incorrect identifications. This review explains the limitations, advantages and challenges of all of these approaches to detecting oxidatively modified proteins, and provides an update on recent literature in which they have been used to detect and quantify protein oxidation in disease.

  4. Comparison of the analytical methods used to determine natural and artificial radionuclides from environmental samples by gamma, alpha and beta spectrometry

    DEFF Research Database (Denmark)

    Pöllänen, Roy; Virtanen, Sinikka; Kämäräinen, Meerit

    In CAMNAR, an extensive interlaboratory exercise on the analytical methods used to determine several radionuclides present in the environmental samples was organized. Activity concentration of different natural radionuclides, such as Rn-222, Pb-210, Po-210, K-40, Ra-226, Ra-228 and isotopes...... of uranium, in addition to artificial Cs-137 and Am-241 were analysed from lake sediment samples and drinking water. The measurement techniques were gamma-ray spectrometry, alpha spectrometry, liquid scintillation counting and inductively coupled plasma mass spectrometry. Twenty six laboratories from nine...

  5. Development of a Method for Rapid Determination of Morpholine in Juices and Drugs by Gas Chromatography-Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Mengsi Cao

    2018-01-01

    Full Text Available A reliable derivatization method has been developed to detect and quantify morpholine in apple juices and ibuprofen with gas chromatography-mass spectrometry. Morpholine can react with sodium nitrite under acidic condition to produce stable and volatile N-nitrosomorpholine derivative. In this experiment, various factors affecting the derivatization and extraction process were optimized, including volume and concentration of hydrochloric acid, quantity of sodium nitrite, derivatization temperature, derivatization time, extraction reagents, and extraction time. The derivative was extracted with dichloromethane and determined by gas chromatography-mass spectrometry. The linearity range of morpholine was 10–500 μg·L−1 with good correlation, and limits of detection (LOD and limits of quantification (LOQ were 7.3 μg·L−1 and 24.4 μg·L−1, respectively. Low, medium, and high concentrations of morpholine were added in apple juices and ibuprofen samples to evaluate standard recovery rate and relative standard deviation. The spiked recovery rate ranged from 94.3% to 109.0%, and the intraday repeatability and interday reproducibility were 2.0%–4.4% and 3.3%–7.0%, respectively. The developed method has good accuracy and precision. This quantitative method for morpholine is simple, sensitive, rapid, and low cost and can successfully be applied to analyze the residual morpholine in apple juices and drug samples.

  6. A new method for the determination of NO2 traces using isotope dilution and mass spectrometry analysis

    International Nuclear Information System (INIS)

    Stevens, C.; Barat, F.; Nguyen Nghi, H.

    1975-01-01

    A new method for the determination of NO 2 traces, in the order of 1ppb (10 -9 ), in atmosphere and stratosphere is described. The method consists in an isotope dilution technique using 15 NO 2 , followed by the reduction of NO 2 to N 2 and a mass spectrometry analysis. A known amount of 15 NO 2 is added to the air samples. Then, NO 2 is separated from H 2 O, HNO 3 , CO 2 and N 2 O and transferred to a SiO 2 reactor by trapping at -196 deg C. In the reactor NO 2 is reduced to N 2 by reaction with electrolytic Cu heated at 580 deg C. The mass 29/mass 30 ratio corresponding to 15 N 14 N and 15 N 15 N is determined by mass spectrometry. The sensitivity of the method depends on the contamination introduced during the analysis of the sample (reagents, separation and measuring devices). The contamination is reproducible and in the order of 4.5+-0.5 10 -2 mm 3 N 2 [fr

  7. Standard test methods for chemical analysis of ceramic whiteware materials using wavelength dispersive X-Ray fluorescence spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover the determination of ten major elements (SiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O, TiO2, P2O5, MnO, and LOI in ceramic whitewares clays and minerals using wavelength dispersive X-ray fluorescence spectrometry (WDXRF). The sample is first ignited, then fused with lithium tetraborate and the resultant glass disc is introduced into a wavelength dispersive X-ray spectrometer. The disc is irradiated with X-rays from an X-ray tube. X-ray photons emitted by the elements in the samples are counted and concentrations determined using previously prepared calibration standards. (1) In addition to 10 major elements, the method provides a gravimetric loss-on-ignition. Note 1—Much of the text of this test method is derived directly from Major element analysis by wavelength dispersive X-ray fluorescence spectrometry, included in Ref (1). 1.2 Interferences, with analysis by WDXRF, may result from mineralogical or other structural effects, line overlaps, and matrix effects. The structure of the...

  8. Magnetic solid phase extraction and static headspace gas chromatography-mass spectrometry method for the analysis of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Cai, Ying; Yan, Zhihong; Wang, Lijia; NguyenVan, Manh; Cai, Qingyun

    2016-01-15

    A magnetic solid phase extraction (MSPE) protocol combining a static headspace gas chromatography coupled to mass spectrometry (HS-GC-MS) method has been developed for extraction, and determination of 16 polycyclic aromatic hydrocarbons (PAHs) in drinking water samples. Magnetic nanoparticles (MNPs) were coated with 3-aminopropyltriethoxysilane and modified by cholesterol chloroformate. Transmission electron microscope, vibrating sample magnetometer, Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy were used to characterize the cholesterol-functionalized sorbents, and the main parameters affecting the extraction as well as HS sampling, such as sorbent amount, extraction time, oven temperature and equilibration time have been investigated and established. Combination with HS sampling, the MSPE procedure was simple, fast and environmentally friendly, without need of any organic solvent. Method validation proved the feasibility of the developed sorbents for the quantitation of the investigated analytes at trace levels obtaining the limit of detection (S/N=3) ranging from 0.20 to 7.8 ng/L. Good values for intra and inter-day precision were obtained (RSDs ≤ 9.9%). The proposed method was successfully applied to drinking water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. A method for getting a finite α in the IR region from an all-order beta function

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhi-Yuan [Chinese Academy of Sciences, Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Beijing (China); University of Chinese Academy of Sciences, School of Physical Sciences, Beijing (China); Zhou, Gao-Liang [Xi' an University of Science and Technology, College of Science, Xi' an (China)

    2017-11-15

    The analytical method of the QCD running coupling constant is extended to a model with an all-order beta function which is inspired by the famous Novikov-Shifman-Vainshtein-Zakharov beta function of N = 1 supersymmetric gauge theories. In the approach presented here, the running coupling is determined by a transcendental equation with non-elementary integral of the running scale μ. In our approach α{sub an}(0), which reads 0.30642, does not rely on any dimensional parameters. This is in accordance with results in the literature on the analytical method of the QCD running coupling constant. The new ''analytically improved'' running coupling constant is also compatible with the property of asymptotic freedom. (orig.)

  10. TiO2-coated Hollow Glass Microspheres with Superhydrophobic and High IR-reflective Properties Synthesized by a Soft-chemistry Method.

    Science.gov (United States)

    Wong, Yinting; Zhong, Dan; Song, Aotian; Hu, Yan

    2017-04-26

    This manuscript proposes a soft-chemistry method to develop superhydrophobic and highly IR-reflective hollow glass microspheres (HGM). The anatase TiO2 and a superhydrophobic agent were coated on the HGM surface in one step. TBT and PFOTES were selected as the Ti source and the superhydrophobic agent, respectively. They were both coated on the HGM, and after the hydrothermal process, the TBT turned to anatase TiO2. In this way, a PFOTES/TiO2-coated HGM (MCHGM) was prepared. For comparison, PFOTES single-coated HGM (F-SCHGM) and TiO2 single-coated HGM (Ti-SCHGM) were synthesized as well. The PFOTES and TiO2 coatings on the HGM surface were demonstrated through X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive detector (EDS) characterizations. The MCHGM showed a higher contact angle (153°) but a lower sliding angle (16°) than F-SCHGM, with a contact angle of 141.2° and a sliding angle of 67°. In addition, both Ti-SCHGM and MCHGM displayed similar IR reflectivity values, which were about 5.8% higher than the original HGM and F-SCHGM. Also, the PFOTES coating barely changed the thermal conductivity. Therefore, F-SCHGM, with a thermal conductivity of 0.0479 W/(m·K), was quite like the original HGM, which was 0.0475 W/(m·K). MCHGM and Ti-SCHGM were also similar. Their thermal conductivity values were 0.0543 W/(m·K) and 0.0543 W/(m·K), respectively. The TiO2 coating slightly increased the thermal conductivity, but with the increase in reflectivity, the overall heat-insulation property was enhanced. Finally, since the IR-reflecting property is provided by the HGM coating, if the coating is fouled, the reflectivity decreases. Therefore, with the superhydrophobic coating, the surface is protected from fouling, and its lifetime is also prolonged.

  11. Improvenments in environmental trace analysis by GC-IR and LC-IR.

    NARCIS (Netherlands)

    Visser, T.; Vredenbregt, M.J.; Jong, A.P.J.M.; Somsen, G.W.; Hankemeier, T.; Velthorst, N.H.; Gooijer, C.; Brinkman, U.A.T.

    1997-01-01

    Research has been carried out to enlarge the potential of infrared (IR) spectrometry as a detector in gas and liquid chromatography (GC and LC). The study has been directed to applications in environmental analysis. Examples of recently obtained results are presented. The analyte detectability of

  12. Sensing cocaine in saliva with attenuated total reflection infrared (ATR-IR) spectroscopy combined with a one-step extraction method

    Science.gov (United States)

    Hans, Kerstin M.-C.; Gianella, Michele; Sigrist, Markus W.

    2012-03-01

    On-site drug tests have gained importance, e.g., for protecting the society from impaired drivers. Since today's drug tests are majorly only positive/negative, there is a great need for a reliable, portable and preferentially quantitative drug test. In the project IrSens we aim to bridge this gap with the development of an optical sensor platform based on infrared spectroscopy and focus on cocaine detection in saliva. We combine a one-step extraction method, a sample drying technique and infrared attenuated total reflection (ATR) spectroscopy. As a first step we have developed an extraction technique that allows us to extract cocaine from saliva to an almost infrared-transparent solvent and to record ATR spectra with a commercially available Fourier Transform-infrared spectrometer. To the best of our knowledge this is the first time that such a simple and easy-to-use one-step extraction method is used to transfer cocaine from saliva into an organic solvent and detect it quantitatively. With this new method we are able to reach a current limit of detection around 10 μg/ml. This new extraction method could also be applied to waste water monitoring and controlling caffeine content in beverages.

  13. Methods in endogenous steroid profiling - A comparison of gas chromatography mass spectrometry (GC-MS) with supercritical fluid chromatography tandem mass spectrometry (SFC-MS/MS).

    Science.gov (United States)

    Teubel, Juliane; Wüst, Bernhard; Schipke, Carola G; Peters, Oliver; Parr, Maria Kristina

    2018-06-15

    In various fields of endocrinology, the determination of steroid hormones synthesised by the human body plays an important role. Research on central neurosteroids has been intensified within the last years, as they are discussed as biomarkers for various cognitive disorders. Their concentrations in cerebrospinal fluid (CSF) are considered to be regulated independently from peripheral fluids. For that reason, the challenging matrix CSF becomes a very interesting specimen for analysis. Concentrations are expected to be very low and available amount of CSF is limited. Thus, a comprehensive method for very sensitive quantification of a set of analytes as large as possible in one analytical aliquot is desired. However, high structural similarities of the selected panel of 51 steroids and steroid sulfates, including numerous isomers, challenges achievement of chromatographic selectivity. Since decades the analysis of endogenous steroids in various body fluids is mainly performed by gas chromatography (GC) coupled to (tandem) mass spectrometry (MS(/MS)). Due to the structure of the steroids of interest, derivatisation is performed to meet the analytical requirements for GC-MS(/MS). Most of the laboratories use a two-step derivatisation in multi-analyte assays that was already published in the 1980s. However, for some steroids this elaborate procedure yields multiple isomeric derivatives. Thus, some laboratories utilize (ultra) high performance liquid chromatography ((U)HPLC)-MS/MS as alternative but, even UHPLC is not able to separate some of the isomeric pairs. Supercritical fluid chromatography (SFC) as an orthogonal separation technique to GC and (U)HPLC may help to overcome these issues. Within this project the two most promising methods for endogenous steroid profiling were investigated and compared: the "gold standard" GC-MS and the orthogonal separation technique SFC-MS/MS. Different derivatisation procedures for gas chromatographic detection were explored and the

  14. Multi- and hyperspectral remote sensing change detection with generalized difference images by the IR-MAD method

    DEFF Research Database (Denmark)

    Nielsen, Allan Aasbjerg; Canty, Morton J.

    2005-01-01

    -based method for determining thresholds for differentiating between change and no-change in the difference images, and for estimating the variance of the no-change observations. This variance is used to establish a single change/no-change image based on the general multivariate difference image. The resulting....../no-change image can be used to establish both change regions and to extract observations based on which a fully automated orthogonal regression analysis based normalization of the multivariate data between the two points in time can be developed. Also, regularization issues typically important in connection...

  15. Application of the radiochemical - and the direct gamma ray spectrometry method to the burnup determination of irradiated uranium oxide

    International Nuclear Information System (INIS)

    Cunha, I.I.L.

    1979-01-01

    The burn up of natural U 3 O 8 that occurs by the action of thermal neutrons was determined, using the radioisotopes 144 Ce, 137 Cs, 103 Ru, 106 Ru and 95 Zr as monitors. The determination of the burn up was made using both destructive and non-destructive methods. In the non-destructive method, the technique of direct gamma-ray spectrometry was used and the radioisotopes mentioned were simultaneously counted in a Ge-Li detector. In the radiochemical method the same radioisotopes were isolated one from the other and from all other fission products before counting. The solvent extraction technique was used for the radiochemical separation of uranium, cerium, cesium and ruthenium. To separate zirconium and niobium, adsorption in silica-gel was used. The extraction agent employed to isolate cesium was dipycrilamine and for the separation of the other radioisotopes Di-(2-Ethyl Hexyl) Phosphoric acid (HDEHP) was used. (Author) [pt

  16. Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action

    DEFF Research Database (Denmark)

    Rabiee, Atefeh; Krüger, Marcus; Ardenkjær-Larsen, Jacob

    2018-01-01

    Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling...... properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type......, IRS-1-/-and IRS-2-/-mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1...

  17. Validation of methods to measure uranium isotopes using magnetic sector mass spectrometry with inductively coupled plasma source

    International Nuclear Information System (INIS)

    Hernandez M, H.; Rios L, M. J.; Romero G, E. T.

    2017-10-01

    The mass spectrometry technique with inductively coupled plasma source (Icp-Ms) has been widely used to measure isotopic ratios of elements toxic to human health. Reason for which, in this work several measurement methods for the analysis of uranium isotopes in different matrices were implemented using magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS). Groundwater, sediment, soil and urine were the matrices analyzed, which were supplied by intercomparison tests conducted by the IAEA and Association for the Promotion of Quality Control of Medical Biology Analysis in Radio-toxicology. The procedures used in the treatment of soil, sediment and water samples were based on US EPA methods. In the case of the urine sample, the preparation was rapid (1:20 dilution). The average of the results obtained in yield of each matrix was 94, 71, 72 and 78% for water, urine, soil and sediment respectively. In addition, the precision in terms of standard relative deviation was less than 5% and the accuracy was less than 4%. In conclusion, the Icp-SFMS is a very sensitive technique for measuring isotopes of U in different matrices. However, careful tuning is necessary, especially in the mass regions of interest 234, 235 and 238 if an external quantification is considered using natural U solutions. (Author)

  18. Analysis of Biological Samples Using Paper Spray Mass Spectrometry: An Investigation of Impacts by the Substrates, Solvents and Elution Methods.

    Science.gov (United States)

    Ren, Yue; Wang, He; Liu, Jiangjiang; Zhang, Zhiping; McLuckey, Morgan N; Ouyang, Zheng

    2013-10-01

    Paper spray has been developed as a fast sampling ionization method for direct analysis of raw biological and chemical samples using mass spectrometry (MS). Quantitation of therapeutic drugs in blood samples at high accuracy has also been achieved using paper spray MS without traditional sample preparation or chromatographic separation. The paper spray ionization is a process integrated with a fast extraction of the analyte from the raw sample by a solvent, the transport of the extracted analytes on the paper, and a spray ionization at the tip of the paper substrate with a high voltage applied. In this study, the influence on the analytical performance by the solvent-substrate systems and the selection of the elution methods was investigated. The protein hemoglobin could be observed from fresh blood samples on silanized paper or from dried blood spots on silica-coated paper. The on-paper separation of the chemicals during the paper spray was characterized through the analysis of a mixture of the methyl violet 2B and methylene blue. The mode of applying the spray solvent was found to have a significant impact on the separation. The results in this study led to a better understanding of the analyte elution, on-paper separation, as well as the ionization processes of the paper spray. This study also help to establish a guideline for optimizing the analytical performance of paper spray for direct analysis of target analytes using mass spectrometry.

  19. Comparative study of the gamma spectrometry method performance in different measurement geometries

    International Nuclear Information System (INIS)

    Diaconescu, C.; Ichim, C.; Bujoreanu, L.; Florea, I.

    2013-01-01

    This paper presents the results obtained by gamma spectrometry on aqueous liquid waste sample using different measurement geometries. A liquid waste sample with known gamma emitters content was measured in three different geometries in order to assess the influence of the geometry on the final results. To obtain low measurement errors, gamma spectrometer was calibrated using a calibration standard with the same physical and chemical characteristics as the sample to be measured. Since the calibration was performed with the source at contact with HPGe detector, the waste sample was also measured, for all the three geometries, at the detector contact. The influence of the measurement geometry on the results was evaluated by computing the relative errors. The measurements performed using three different geometries (250 ml plastic vial, Sarpagan box and 24 ml Tricarb vial) showed that all these geometries may be used to quantify the activity of gamma emitters in different type of radioactive waste. (authors)

  20. Lipidomic analysis of biological samples: Comparison of liquid chromatography, supercritical fluid chromatography and direct infusion mass spectrometry methods.

    Science.gov (United States)

    Lísa, Miroslav; Cífková, Eva; Khalikova, Maria; Ovčačíková, Magdaléna; Holčapek, Michal

    2017-11-24

    Lipidomic analysis of biological samples in a clinical research represents challenging task for analytical methods given by the large number of samples and their extreme complexity. In this work, we compare direct infusion (DI) and chromatography - mass spectrometry (MS) lipidomic approaches represented by three analytical methods in terms of comprehensiveness, sample throughput, and validation results for the lipidomic analysis of biological samples represented by tumor tissue, surrounding normal tissue, plasma, and erythrocytes of kidney cancer patients. Methods are compared in one laboratory using the identical analytical protocol to ensure comparable conditions. Ultrahigh-performance liquid chromatography/MS (UHPLC/MS) method in hydrophilic interaction liquid chromatography mode and DI-MS method are used for this comparison as the most widely used methods for the lipidomic analysis together with ultrahigh-performance supercritical fluid chromatography/MS (UHPSFC/MS) method showing promising results in metabolomics analyses. The nontargeted analysis of pooled samples is performed using all tested methods and 610 lipid species within 23 lipid classes are identified. DI method provides the most comprehensive results due to identification of some polar lipid classes, which are not identified by UHPLC and UHPSFC methods. On the other hand, UHPSFC method provides an excellent sensitivity for less polar lipid classes and the highest sample throughput within 10min method time. The sample consumption of DI method is 125 times higher than for other methods, while only 40μL of organic solvent is used for one sample analysis compared to 3.5mL and 4.9mL in case of UHPLC and UHPSFC methods, respectively. Methods are validated for the quantitative lipidomic analysis of plasma samples with one internal standard for each lipid class. Results show applicability of all tested methods for the lipidomic analysis of biological samples depending on the analysis requirements

  1. Multiclass mycotoxin analysis in edible oils using a simple solvent extraction method and liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Eom, Taeyong; Cho, Hyun-Deok; Kim, Junghyun; Park, Mihee; An, Jinyoung; Kim, Moosung; Kim, Sheen-Hee; Han, Sang Beom

    2017-11-01

    A simple and rapid method for the simultaneous determination of 11 mycotoxins - aflatoxins B 1 , B 2 , G 1 and G 2 ; fumonisins B 1 , B 2 and B 3 ; ochratoxin A; zearalenone; deoxynivalenol; and T-2 toxin - in edible oils was established using liquid chromatography tandem mass spectrometry (LC-MS/MS). In this study, QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe), QuEChERS with dispersive liquid-liquid microextraction, and solvent extraction were examined for sample preparation. Among these methods, solvent extraction with a mixture of formic acid/acetonitrile (5/95, v/v) successfully extracted all target mycotoxins. Subsequently, a defatting process using n-hexane was employed to remove the fats present in the edible oil samples. Mass spectrometry was carried out using electrospray ionisation in polarity switching mode with multiple reaction monitoring. The developed LC-MS/MS method was validated by assessing the specificity, linearity, recovery, limit of quantification (LOQ), accuracy and precision with reference to Commission Regulation (EC) 401/2006. Mycotoxin recoveries of 51.6-82.8% were achieved in addition to LOQs ranging from 0.025 ng/g to 1 ng/g. The edible oils proved to be relatively uncomplicated matrices and the developed method was applied to 9 edible oil samples, including soybean oil, corn oil and rice bran oil, to evaluate potential mycotoxin contamination. The levels of detection were significantly lower than the international regulatory standards. Therefore, we expect that our developed method, based on simple, two-step sample preparation process, will be suitable for the large-scale screening of mycotoxin contamination in edible oils.

  2. A high-throughput method for liquid chromatography-tandem mass spectrometry determination of plasma alkylresorcinols, biomarkers of whole grain wheat and rye intake

    DEFF Research Database (Denmark)

    Ross, Alastair B; Svelander, Cecilia; Savolainen, Otto I

    2016-01-01

    supported extraction methods for extracting alkylresorcinols from plasma and improved a normal-phase liquid chromatography coupled to a tandem mass spectrometer method to reduce sample analysis time. The method was validated and compared with gas chromatography-mass spectrometry analysis. Sample preparation...

  3. Determination of mercury in seawater by total reflection x-ray fluorescence spectrometry after an electrochemical preconcentration method

    International Nuclear Information System (INIS)

    Ritschel, A.; Chinea Cano, E.; Wobrauschek, P.; Kuntner, C.; Durakbasa, M.N.

    2000-01-01

    A new combined method of electrodeposition of trace elements on metallic plates with subsequent total-reflection x-ray fluorescence spectrometry (TXRF) is proposed for the determination of trace metals in natural waters. The elements of interest are electroplated on highly polished niobium discs which are used as sample carriers for the TXRF measurement. The electrochemical preconcentration is performed in a flow cell under a controlled working electrode potential. The preconcentration step involves only very little manipulation which minimizes the risk of contamination of the sample. The method was investigated by analyzing inorganic mercury in sea water. A detection limit of 7 ngl -1 could be achieved for mercury in a 40 ml sea water sample. (author)

  4. Development of precise analytical methods for strontium and lanthanide isotopic ratios using multiple collector inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Ohno, Takeshi; Takaku, Yuichi; Hisamatsu, Shun'ichi

    2007-01-01

    We have developed precise analytical methods for strontium and lanthanide isotopic ratios using multiple collector-ICP-mass spectrometry (MC-ICP-MS) for experimental and environmental studies of their behavior. In order to obtain precise isotopic data using MC-ICP-MS, the mass discrimination effect was corrected by an exponential law correction method. The resulting isotopic data demonstrated that highly precise isotopic analyses (better than 0.1 per mille as 2SD) could be achieved. We also adopted a de-solvating nebulizer system to improve the sensitivity. This system could minimize the water load into the plasma and provided about five times larger intensity of analyte than a conventional nebulizer system did. (author)

  5. Rapid method for the sequential measurement of isotopes of Am and Pu in liquid matrices by alpha spectrometry

    International Nuclear Information System (INIS)

    Mantero Cabrera, J.

    2014-01-01

    : In radiological emergencies it's necessary a fast response from the laboratories in the quantification of certain radionuclides, in order to take decisions. In these cases, is the reaction time the key parameter to consider (without neglecting the quality of the measurement). In this work, it is shown a method for aqueous matrices that generates Pu and Am isotopes sources in one single day of work, to be measured subsequently by alpha spectrometry. The developed methodology has been validated through its application to reference samples and also taking part intercom- parison exercises, having in both cases, satisfactory results. This way, we check the validity of this fast method that let us generate in 24 hours (since the sample arrives our laboratory), one measurement with a Minimun Detectable Activity (MDA) of about 0.004Bq/L for Pu and Am isotopes in liquid matrices. [es

  6. Computational methods for metabolomic data analysis of ion mobility spectrometry data-reviewing the state of the art

    DEFF Research Database (Denmark)

    Hauschild, Anne-Christin; Schneider, Till; Pauling, Josch

    2012-01-01

    that MCC/IMS coupled with sophisticated computational methods has the potential to successfully address a broad range of biomedical questions. While we can solve most of the data pre-processing steps satisfactorily, some computational challenges with statistical learning and model validation remain.......Ion mobility spectrometry combined with multi-capillary columns (MCC/IMS) is a well known technology for detecting volatile organic compounds (VOCs). We may utilize MCC/IMS for scanning human exhaled air, bacterial colonies or cell lines, for example. Thereby we gain information about the human...... of computational approaches for analyzing the huge amount of emerging data sets. Here, we will review the state of the art and highlight existing challenges. First, we address methods for raw data handling, data storage and visualization. Afterwards we will introduce de-noising, peak picking and other pre...

  7. Development of an extraction method for the determination of dissolved organic radiocarbon in seawater by accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Tanaka, Takayuki; Otosaka, Shigeyoshi; Togawa, Orihiko; Amano, Hikaru

    2009-01-01

    We developed an extraction method for accurately and reproducibly determining dissolved organic radiocarbon in seawater by ultraviolet oxidation of dissolved organic carbon and subsequent accelerator mass spectrometry. We determined the irradiation time required for oxidation of the dissolved organic carbon. By modifying the experimental apparatus, we decreased contamination by dead carbon, which came mainly from petrochemical products in the apparatus and from the incursion of carbon dioxide from the atmosphere. The modifications decreased the analytical blank level to less than 1% of sample size, a percentage that had not previously been achieved. The recovery efficiency was high, 95±1%. To confirm both the accuracy and reproducibility of the method, we tested it by analyzing an oxalic acid radiocarbon reference material and by determining the dissolved organic carbon in surface seawater samples. (author)

  8. Isotope dilution liquid chromatography - mass spectrometry methods for fat- and water-soluble vitamins in nutritional formulations.

    Science.gov (United States)

    Phinney, Karen W; Rimmer, Catherine A; Thomas, Jeanice Brown; Sander, Lane C; Sharpless, Katherine E; Wise, Stephen A

    2011-01-01

    Vitamins are essential to human health, and dietary supplements containing vitamins are widely used by individuals hoping to ensure they have adequate intake of these important nutrients. Measurement of vitamins in nutritional formulations is necessary to monitor regulatory compliance and in studies examining the nutrient intake of specific populations. Liquid chromatographic methods, primarily with UV absorbance detection, are well established for both fat- and water-soluble measurements, but they do have limitations for certain analytes and may suffer from a lack of specificity in complex matrices. Liquid chromatography-mass spectrometry (LC-MS) provides both sensitivity and specificity for the determination of vitamins in these matrices, and simultaneous analysis of multiple vitamins in a single analysis is often possible. In this work, LC-MS methods were developed for both fat- and water-soluble vitamins and applied to the measurement of these analytes in two NIST Standard Reference Materials. When possible, stable isotope labeled internal standards were employed for quantification.

  9. Liquid chromatography tandem mass spectrometry method for simultaneous determination of metoprolol tartrate and ramipril in human plasma.

    Science.gov (United States)

    Gowda, K Veeran; Mandal, Uttam; Senthamil Selvan, P; Sam Solomon, W D; Ghosh, Animesh; Sarkar, Amlan Kanti; Agarwal, Sangita; Nageswar Rao, T; Pal, Tapan Kumar

    2007-10-15

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of metoprolol tartrate (MT) and ramipril, in human plasma. Both the drugs were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v). The chromatographic separation was performed on a reversed-phase C8 column with a mobile phase of 10 mM ammonium formate-methanol (3:97, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The method was validated over the concentration range of 5-500 ng/ml for metoprolol and ramipril in human plasma. The precursor to product ion transitions of m/z 268.0-103.10 and m/z 417.20-117.20 were used to measure metoprolol and ramipril, respectively.

  10. Collaborative trial validation study of two methods, one based on high performance liquid chromatography-tandem mass spectrometry and on gas chromatography-mass spectrometry for the determination of acrylamide in bakery and potato products.

    Science.gov (United States)

    Wenzl, Thomas; Karasek, Lubomir; Rosen, Johan; Hellenaes, Karl-Erik; Crews, Colin; Castle, Laurence; Anklam, Elke

    2006-11-03

    A European inter-laboratory study was conducted to validate two analytical procedures for the determination of acrylamide in bakery ware (crispbreads, biscuits) and potato products (chips), within a concentration range from about 20 microg/kg to about 9000 microgg/kg. The methods are based on gas chromatography-mass spectrometry (GC-MS) of the derivatised analyte and on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) of native acrylamide. Isotope dilution with isotopically labelled acrylamide was an integral part of both methods. The study was evaluated according to internationally accepted guidelines. The performance of the HPLC-MS/MS method was found to be superior to that of the GC-MS method and to be fit-for-the-purpose.

  11. Statistical signal processing for gamma spectrometry: application for a pileup correction method; Traitement statistique du signal spectrometrique: etude du desempilement de spectre en energie pour la spectrometrie gamma

    Energy Technology Data Exchange (ETDEWEB)

    Trigano, T

    2005-12-15

    The main objective of gamma spectrometry is to characterize the radioactive elements of an unknown source by studying the energy of the emitted photons. When a photon interacts with a detector, its energy is converted into an electrical pulse. The histogram obtained by collecting the energies can be used to identify radioactive elements and measure their activity. However, at high counting rates, perturbations which are due to the stochastic aspect of the temporal signal can cripple the identification of the radioactive elements. More specifically, since the detector has a finite resolution, close arrival times of photons which can be modeled as an homogeneous Poisson process cause pile-ups of individual pulses. This phenomenon distorts energy spectra by introducing multiple fake spikes and prolonging artificially the Compton continuum, which can mask spikes of low intensity. The objective of this thesis is to correct the distortion caused by the pile-up phenomenon in the energy spectra. Since the shape of photonic pulses depends on many physical parameters, we consider this problem in a nonparametric framework. By introducing an adapted model based on two marked point processes, we establish a nonlinear relation between the probability measure associated to the observations and the probability density function we wish to estimate. This relation is derived both for continuous and for discrete time signals, and therefore can be used on a large set of detectors and from an analog or digital point of view. It also provides a framework to this problem, which can be considered as a problem of nonlinear density deconvolution and nonparametric density estimation from indirect measurements. Using these considerations, we propose an estimator obtained by direct inversion. We show that this estimator is consistent and almost achieves the usual rate of convergence obtained in classical nonparametric density estimation in the L{sup 2} sense. We have applied our method to a set

  12. Relativistic band-structure calculations for CeTIn sub 5 (T=Ir and Co) and analysis of the energy bands by using tight-binding method

    CERN Document Server

    Maehira, T; Ueda, K; Hasegawa, A

    2003-01-01

    In order to investigate electronic properties of recently discovered heavy fermion superconductors CeTIn sub 5 (T=Ir and Co), we employ the relativistic linear augmented-plane-wave (RLAPW) method to clarify the energy band structures and Fermi surfaces of those materials. The obtained energy bands mainly due to the large hybridization between Ce 4 f and In 5 p states well reproduce the Fermi surfaces consistent with the de Haas-van Alphen experimental results. However, when we attempt to understand magnetism and superconductively in CeTIn sub 5 from the microscopic viewpoint, the energy bands obtained in the RLAPW method are too complicated to analyze the system by further including electron correlations. Thus, it is necessary to prepare a more simplified model, keeping correctly the essential characters of the energy bands obtained in the band-structure calculation. For the purpose, we construct a tight-binding model for CeTIn sub 5 by including f-f and p-p hoppings as well as f-p hybridization, which are ex...

  13. Rapid Quadrupole-Time-of-Flight Mass Spectrometry Method Quantifies Oxygen-Rich Lignin Compound in Complex Mixtures

    Science.gov (United States)

    Boes, Kelsey S.; Roberts, Michael S.; Vinueza, Nelson R.

    2018-03-01

    Complex mixture analysis is a costly and time-consuming task facing researchers with foci as varied as food science and fuel analysis. When faced with the task of quantifying oxygen-rich bio-oil molecules in a complex diesel mixture, we asked whether complex mixtures could be qualitatively and quantitatively analyzed on a single mass spectrometer with mid-range resolving power without the use of lengthy separations. To answer this question, we developed and evaluated a quantitation method that eliminated chromatography steps and expanded the use of quadrupole-time-of-flight mass spectrometry from primarily qualitative to quantitative as well. To account for mixture complexity, the method employed an ionization dopant, targeted tandem mass spectrometry, and an internal standard. This combination of three techniques achieved reliable quantitation of oxygen-rich eugenol in diesel from 300 to 2500 ng/mL with sufficient linearity (R2 = 0.97 ± 0.01) and excellent accuracy (percent error = 0% ± 5). To understand the limitations of the method, it was compared to quantitation attained on a triple quadrupole mass spectrometer, the gold standard for quantitation. The triple quadrupole quantified eugenol from 50 to 2500 ng/mL with stronger linearity (R2 = 0.996 ± 0.003) than the quadrupole-time-of-flight and comparable accuracy (percent error = 4% ± 5). This demonstrates that a quadrupole-time-of-flight can be used for not only qualitative analysis but also targeted quantitation of oxygen-rich lignin molecules in complex mixtures without extensive sample preparation. The rapid and cost-effective method presented here offers new possibilities for bio-oil research, including: (1) allowing for bio-oil studies that demand repetitive analysis as process parameters are changed and (2) making this research accessible to more laboratories. [Figure not available: see fulltext.

  14. Development of liquid chromatography-tandem mass spectrometry methods for the quantitation of Anisakis simplex proteins in fish.

    Science.gov (United States)

    Fæste, Christiane Kruse; Moen, Anders; Schniedewind, Björn; Haug Anonsen, Jan; Klawitter, Jelena; Christians, Uwe

    2016-02-05

    The parasite Anisakis simplex is present in many marine fish species that are directly used as food or in processed products. The anisakid larvae infect mostly the gut and inner organs of fish but have also been shown to penetrate into the fillet. Thus, human health can be at risk, either by contracting anisakiasis through the consumption of raw or under-cooked fish, or by sensitisation to anisakid proteins in processed food. A number of different methods for the detection of A. simplex in fish and products thereof have been developed, including visual techniques and PCR for larvae tracing, and immunological assays for the determination of proteins. The recent identification of a number of anisakid proteins by mass spectrometry-based proteomics has laid the groundwork for the development of two quantitative liquid chromatography-tandem mass spectrometry methods for the detection of A. simplex in fish that are described in the present study. Both, the label-free semi-quantitative nLC-nESI-Orbitrap-MS/MS (MS1) and the heavy peptide-applying absolute-quantitative (AQUA) LC-TripleQ-MS/MS (MS2) use unique reporter peptides derived from anisakid hemoglobin and SXP/RAL-2 protein as analytes. Standard curves in buffer and in salmon matrix showed limits of detection at 1μg/mL and 10μg/mL for MS1 and 0.1μg/mL and 2μg/mL for MS2. Preliminary method validation included the assessment of sensitivity, repeatability, reproducibility, and applicability to incurred and naturally-contaminated samples for both assays. By further optimization and full validation in accordance with current recommendations the LC-MS/MS methods could be standardized and used generally as confirmative techniques for the detection of A. simplex protein in fish. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. A simple and selective liquid chromatography- tandem mass spectrometry method for determination of ε-aminocaproic acid in human plasma

    Directory of Open Access Journals (Sweden)

    Ganesh S. Moorthy

    2015-07-01

    Full Text Available Understanding the clinical pharmacology of the antifibrinolytic drug epsilon-aminocaproic acid (EACA is critical for rational drug administration in children. The aim of this study is to develop a reliable assay for the determination of EACA in human plasma. We describe a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS assay for EACA in human plasma. Sample preparation involved plasma dilution (1:2040, followed by reversed-phase chromatographic separation and selective detection using tandem mass spectrometry. EACA had a linear range of 1 - 250 μg/mL. The intraday precision based on the standard deviation of replicates of quality control samples ranged from 4.7 to 10.4% and the accuracy ranged from 92-106%. The interday precision ranged from 4.6 to 9.8% and the accuracy ranged from 95-103%. Stability studies showed that EACA was stable during the conditions for sample preparation and storage. The described method is robust and successfully employed for clinical studies of EACA in children

  16. Comparison of in-situ gamma ray spectrometry measurements with conventional methods in determination natural and artificial nuclides in soil

    International Nuclear Information System (INIS)

    Al-Masri, M. S.; Doubal, A. W.

    2010-12-01

    Two nuclear analytical techniques (In-Situ Gamma ray spectrometry and laboratory gamma ray spectrometry) for determination of natural and artificial radionuclides in soil have been validated. The first technique depends on determination of radioactivity content of representative samples of the studied soil after laboratory preparation, while the second technique is based on direct determination of radioactivity content of soil using in-situ gamma-ray spectrometer. Analytical validation parameter such as detection limits, repeatability, reproducibility in addition to measurement uncertainties were estimated and compared for both techniques. Comparison results have shown that the determination of radioactivity in soil should apply the two techniques together where each of techniques is characterized by its low detection limit and uncertainty suitable for defined application of measurement. Radioactive isotopes in various locations were determined using the two methods by measuring 40 k, 238 U,and 137 Cs. The results showed that there are differences in attenuation factors due to soil moisture content differences; wet weight corrections should be applied when the two techniques are compared. (author)

  17. Assay of cortisol with a radioimmunoassay method calibrated by isotope dilution-mass spectrometry. A Nordic collaborative study

    International Nuclear Information System (INIS)

    Lantto, O.; Lindback, B.; Aakvaag, A.; Bjoerkhem, I.; Damkjaer-Nielsen, M.; Pomoell, U.M.; Helsinki University Hospital

    1983-01-01

    A reference method for serum cortisol, based on isotope dilution-mass spectrometry (ID-MS), was compared with a modified commercial RIA method. The modification solely concerned the calibration standards used in the RIA method. These were replaced by a series of human serum samples, in which the concentration of cortisol had been determined by the reference ID-MS method. Samples were selected to cover the whole range of the standard curve. Serum samples from healthy, untreated subjects with cortisol concentrations 270-1134 nmol/l were analysed with the ID-MS calibrated RIA method in four laboratories, one in each of the four Nordic countries. Mean values based on results from all four laboratories were almost identical with the values obtained with the reference method. Serum samples from 11 patients with endocrine disorders with cortisol concentrations 31-916 nmol/l were analysed in three of the four laboratories. In three of the samples significant differences were observed between the values obtained with the ID-MS and the ID-MS calibrated RIA method. The value obtained with the ID-MS calibrated RIA was however always more accurate than the corresponding value obtained with RIA with the use of a commercial calibration standard. (author)

  18. Determination of burnup for IEAR-1 fuel elements by non destructive method of gamma spectrometry

    International Nuclear Information System (INIS)

    Madi Filho, T.; Holland, L.

    1982-01-01

    Burnup determination, by non-destructive gamma spectrometry of spent fuel with high and low activity of IEAR-1 reactor, using Cs-137 as burnup monitor, were done. To measure the Cs-137 distribution in these elements a Ge(Li) detector, with volume equal to 73,7 cm 3 , in two measurement systems with defined geometry and good colimation, was used. The IEA-14 taken from the core about 20 years ago, presents a gamma spectra due to Cs-137. The IEA-80, with cooling time approximately to 5 years, shows a more complex gamma spectrum due to other fission products still found in significant quantities. The IEA-14 measures were done in a measurement system used outside the reactor pool (S.I.), being the global efficiency of this system obtained by using a plane, calibrated and extense Ag-110 m source. Detailed measures of gamma transmission, using Cs-137 as a calibrated and punctiforme source, showed the high homogenity of the fuel plates. (E.G.) [pt

  19. Fast methods of fungal and bacterial identification. MALDI-TOF mass spectrometry, chromogenic media.

    Science.gov (United States)

    Siller-Ruiz, María; Hernández-Egido, Sara; Sánchez-Juanes, Fernando; González-Buitrago, José Manuel; Muñoz-Bellido, Juan Luis

    2017-05-01

    MALDI-TOF mass spectrometry is now a routine resource in Clinical Microbiology, because of its speed and reliability in the identification of microorganisms. Its performance in the identification of bacteria and yeasts is perfectly contrasted. The identification of mycobacteria and moulds is more complex, due to the heterogeneity of spectra within each species. The methodology is somewhat more complex, and expanding the size of species libraries, and the number of spectra of each species, will be crucial to achieve greater efficiency. Direct identification from blood cultures has been implemented, since its contribution to the management of severe patients is evident, but its application to other samples is more complex. Chromogenic media have also contributed to the rapid diagnosis in both bacteria and yeast, since they accelerate the diagnosis, facilitate the detection of mixed cultures and allow rapid diagnosis of resistant species. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

  20. Performance characteristics of a Bioassay method for plutonium using thermal ionisation mass spectrometry (TIMS)

    Energy Technology Data Exchange (ETDEWEB)

    Linauskas, S.H.; Elliot, N.L.; Paterson, L.M.; Totland, M.M

    2003-01-01

    Plutonium-in-urine analysis by radiochemical isolation of Pu followed by thermal ionisation mass spectrometry (TIMS) is capable of high sensitivity and precision measurements {sup 239}Pu and {sup 240}Pu. Bias and precision estimates for the TIMS bioassay program at Chalk River Laboratories easily met the ANSI N13.30 performance criteria standards with {sup 239}Pu results of 1.5% and 3.0%, respectively. Analytical blanks derived from water, artificial urine and true urine samples did not produce any statistically different results. During a four-year period of development and implementation of {sup 239}Pu measurements by TIMS, average sample blank values were reduced from 3.9 fg (9.0 {mu}Bq) to 0.57 fg (1.3 {mu}Bq). This reduction was achieved through rigorous application of clean-room handling techniques throughout sample processing. Blank data were found to follow a Iognormal distribution, and current detection limit parameters for L{sub c} and L{sub d} at the 95% significance levels are 0.85 fg {sup 239}Pu (2.0 {mu}Bq) and 1.3 fg {sup 239}Pu (3.0 {mu}Bq), respectively. Detection limits in this range are expected to be sufficient to identify intakes of Pu/Am mixtures at levels that are around one-twentieth of an ALl or better under routine monitoring situations for ICRP Type S and Type M inhalation solubility classes. (author)

  1. Burn up determination of IEAR-1 fuel elements by non destructive gamma ray spectrometry method

    International Nuclear Information System (INIS)

    Soares, A.J.

    1977-01-01

    Measurement of nuclear fuel burn up by non destructive gamma ray spectrometry is discussed, and results of such measurements, made at the Instituto de Energia Atomica (IEA), are given. Specifically, the burn up of an MTR (Material Testing Reactor) fuel element removed from the IEAR-1 swimming pool reactor in 1958 is evaluated from the measured Cs-137 activity, which gives a single 661,6 keV gamma ray. Due to the long decay time of the test element, no other fission decay product activity could be detected. Analysis of measurements, made with a 3'' x 3'' NaI(Tl) detector at 330 distinct points of the element, showed the total burn up to 3.3 +- -+ 0.8 mg. This is in agreement with a calculated value. As the maximum temperature of IEAR-1 fuel elements is of the order of 40 0 C, migration effects of Cs-137 was not considered, this being significant only at fuel temperature in excess of 1000 0 C [pt

  2. Liquid chromatography tandem mass spectrometry method for the estimation of lamotrigine in human plasma: Application to a pharmacokinetic study

    Directory of Open Access Journals (Sweden)

    Santosh Ghatol

    2013-04-01

    Full Text Available A reliable, selective and sensitive liquid chromatography tandem mass spectrometry method was developed and validated for the quantification of lamotrigine in human plasma using lamotrigine-13C3, d3 as an internal standard. Analyte and internal standard were extracted from human plasma by solid-phase extraction and detected in positive ion mode by tandem mass spectrometry with electrospray ionization (ESI interface. Chromatographic separation was performed on a Chromolith® SpeedROD; RP-18e column (50−4.6 mm i.d. using acetonitrile: 5±0.1 mM ammonium formate solution (90:10, v/v as the mobile phase at a flow rate of 0.500 mL/min. The calibration curves were linear over the range of 5.02–1226.47 ng/mL with the lower limit of quantitation validated at 5.02 ng/mL. The analytes were found stable in human plasma through three freeze (−20 °C-thaw (ice-cold water bath cycles and under storage on bench-top in ice-cold water bath for at least 6.8 h, and also in the mobile phase at 10 °C for at least 57 h. The method has shown good reproducibility, as the intra- and inter-day precisions were within 3.0%, while the accuracies were within ±6.0% of nominal values. The validated LC–MS/MS method was applied for the evaluation of pharmacokinetic and bioequivalence parameters of lamotrigine after an oral administration of 50 mg lamotrigine tablet to thirty-two healthy adult male volunteers. Keywords: Lamotrigine, Liquid chromatography/tandem mass spectrometry, Solid phase extraction, Pharmacokinetic study

  3. Development of a liquid chromatography tandem mass spectrometry method for iothalamate measurement to assess renal function for potential kidney donation.

    Science.gov (United States)

    Rhea, Jeanne M; Ritchie, James C; Molinaro, Ross J

    2013-05-01

    Chronic kidney disease often goes undetected due to the insensitivity of current methods to accurately assess glomerular filtration rate (GFR) in early stages of renal dysfunction. The clearance of exogenously introduced iothalamate, a commonly used radiopaque agent, is an alternative to inulin clearance for the assessment of renal function and its use in calculating GFR can serve as a screening tool for kidney transplant donors. A method was developed to measure iothalamate in plasma and urine samples by HPLC combined with electrospray positive ionization tandem mass spectrometry (MS/MS). Iothalamate is isolated from plasma by methanol extraction and urine using a quick-spin filtration approach, then monitored by multiple reaction monitoring using the hydrogen adduct mass transitions. Iohexol was used as an internal standard. Iothalamate was measured within an analytical run time of 5 min, with a lower limit of quantification of 18.75 ng/ml. The intraassay and interassay variations of the plasma and urine iothalamate assays were both calculated using the patient's urine flow rate and plasma and urine iothalamate values. Linear correlations tested by LC-MS/MS and an accepted capillary electrophoresis (CE) assay showed similar results (GFR, r=0.92, Sy/x=10.3). We developed and validated an LC-MS/MS method for quantitating iothalamate in plasma and urine to calculate GFR used for screening potential kidney donors in our hospital system. A less sensitive mass spectrometry system does not sacrifice analytical or clinical sensitivity for measuring GFR. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Determination of mercury in ash and soil samples by oxygen flask combustion method-Cold vapor atomic fluorescence spectrometry (CVAFS)

    International Nuclear Information System (INIS)

    Geng Wenhua; Nakajima, Tsunenori; Takanashi, Hirokazu; Ohki, Akira

    2008-01-01

    A simple method was developed for the determination of mercury (Hg) in coal fly ash (CFA), waste incineration ash (WIA), and soil by use of oxygen flask combustion (OFC) followed by cold vapor atomic fluorescence spectrometry (CVAFS). A KMnO 4 solution was used as an absorbent in the OFC method, and the sample containing a combustion agent and an ash or soil sample was combusted by the OFC method. By use of Hg-free graphite as the combustion agent, the determination of Hg in ash and soil was successfully carried out; the Hg-free graphite was prepared by use of a mild pyrolysis procedure at 500 deg. C. For six certified reference materials (three CFA samples and three soil samples), the values of Hg obtained by this method were in good agreement with the certified or reference values. In addition, real samples including nine CFAs collected from some coal-fired power plants, five WIAs collected from waste incineration plants, and two soils were analyzed by the present method, and the data were compared to those from microwave-acid digestion (MW-AD) method

  5. A self-sufficient and general method for self-absorption correction in gamma-ray spectrometry using GEANT4

    International Nuclear Information System (INIS)

    Hurtado, S.; Villa, M.; Manjon, G.; Garcia-Tenorio, R.

    2007-01-01

    This paper presents a self-sufficient and general method for measurement of the activity of low-level gamma-emitters in voluminous samples by gamma-ray spectrometry with a coaxial germanium detector. Due to self-absorption within the sample, the full-energy peak efficiency of low-energy emitters in semiconductor gamma-spectrometers depends strongly on a number of factors including sample composition, density, sample size and gamma-ray energy. As long as those commented factors are well characterized, the influence of self-absorption in the full-energy peak efficiency of low-energy emitters can be calculated using Monte Carlo method based on GEANT4 code for each individual sample. However this task is quite tedious and time consuming. In this paper, we propose an alternative method to determine this influence for voluminous samples of unknown composition. Our method combines both transmission measurements and Monte Carlo simulations, avoiding the application of Monte Carlo full-energy peak efficiency determinations for each individual sample. To test the accuracy and precision of the proposed method, we have calculated 210 Pb activity in sediments samples from an estuary located in the vicinity of several phosphates factories with the proposed method, comparing the obtained results with the ones determined in the same samples using two alternative radiometric techniques

  6. Developments in gamma-ray spectrometry: systems, software, and methods-II. 4. High-Performance Digital Gamma-Ray Spectrometry

    International Nuclear Information System (INIS)

    Michael Momayezi

    2001-01-01

    This paper reviews recent advances in the field of digital spectrometry made by researchers at X-Ray Instrumentation Associates. All XIA spectrometers are based on a core architecture, which employs digitizing the input signal without shaping and applying all basic data processing in real time to the digital data stream coming out of the wave form digitizer. The real-time digital data processing includes filtering, triggering, pileup rejection, and even pulse shape analysis. In this paper we will describe some of those methods that go beyond emulating a conventional analog system in a digital environment. Rather we will concentrate mainly on methods that have no real equivalent in the analog world. In conventional spectrometers pulse pileup recognition is hardwired and serves a single purpose, namely to reject signals that occur too close to each other to allow for a precise measurement of their amplitude. For a digital device, which can also record wave forms, that would be an unfortunate limitation. The study of very short-lived radioactive isotopes is a case in point. If such an isotope is implanted into a detector in which it then decays by charged particle emission, the signature for the sought-after isotope is that of an implant pulse followed by one or more decay pulses from the isotope and its daughters. If the decay products can be absorbed in the same detector channel, as is the case for proton and alpha emitters in a Si-strip detector, then the isotope decay will show up as a pulse train coming from that detector channel. The difficulty usually is to find the few isotopes of interest amongst a huge background of long-lived or stable isotopes. With programmable pileup recognition logic it is possible to trigger specifically on pulse trains, rather than single pulses, thereby picking out very selectively the isotopes of interest. Analyzing the pulse shape of the incoming preamplifier signal proves to be very useful in many applications. The most obvious

  7. Relaxation dynamics of the LH2 complex from a photosynthetic purple bacterium Thiorhodospira sibirica studied by the near-IR femtosecond pump-probe method

    International Nuclear Information System (INIS)

    Razjivin, A P; Pishchal'nikov, R Yu; Kozlovskii, V S; Kompanets, V O; Chekalin, Sergei V; Moskalenko, A A; Makhneva, Z K

    2005-01-01

    Photoinduced changes in the absorption spectrum of the LH2 (B800-830-850) complex from a Thiorhodospira sibirica (Trs. sibirica) bacterium are studied by the pump-probe method. The complex has the anomalous absorption spectrum exhibiting three bands in the near-IR region at 793, 826.5, and 846.5 nm. At room temperature, the excitation energy transfer from the B800, B830, and B859 bands was detected with the time constants τ 1 ∼0.5 ps, τ 2 ∼2.5 ps, and τ 3 of the order of a few hundreds of picoseconds, respectively. A rapid energy transfer from the B830 band compared to energy transfer from the B850 band (τ 2 ||τ 3 ) suggests that all the three bands belong to the same complex (i.e., that the LH2 complex from Trs. sibirica is homogeneous). A slower energy transfer (by three - five times) from the B830 band of the LH2 complex from Trs. sibirica compared to energy transfer from the B800 band of the LH2 complexes (B800-850 and especially B800-820) from other purple bacteria suggests that the electronic structures of ensembles of bacteriochlorophyll molecules in these complexes are substantially different. (laser applications and other topics in quantum electronics)

  8. METHOD 544. DETERMINATION OF MICROCYSTINS AND NODULARIN IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY (LC/MS/MS)

    Science.gov (United States)

    Method 544 is an accurate and precise analytical method to determine six microcystins (including MC-LR) and nodularin in drinking water using solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS). The advantage of this SPE-LC/MS/MS is its sensi...

  9. Applying a method of chemical separation and mass spectrometry for the determination of radium-226 in surface water

    International Nuclear Information System (INIS)

    Sibello Hernandez, Rita Y; Cozzella, Maria Letizia; Guillen Arruebarrena, Aniel

    2014-01-01

    Radium-226 ( 226 Ra) is a naturally occurring radionuclide, alpha emitter with half-life of 1 622 years originating from uranium-238 ( 238 U). Its presence in drinking water is a major radiological hazards, which requires constant monitoring. The analytical techniques used in the determination of 226 Ra generally require the establishment of secular equilibrium and/or tedious separation of other elements. The main objective of this paper is to demonstrate the efficiency and speed of a method of preconcentration and separation of 226 Ra in natural water samples using coprecipitation with MnO 2 radius and purification by cation exchange resin Dowex 50WX8. Measurement technique was Quadrupole Mass Spectrometry and associated induced plasma ICP-Q-MS. The 226 Ra values obtained are in the range of 0,010-0,219 pg/L in natural waters analyzed

  10. Estimation of accumulated dose of radiation by the method of ESR-spectrometry of dental enamel of mammals

    International Nuclear Information System (INIS)

    Serezhenkov, V.A.; Moroz, I.A.; Vanin, A.F.; Klevezal, G.A.

    1997-01-01

    ESR-spectrometry was used to investigate radiation-induced paramagnetic centers in enamel of mammals: carnivores (polar bear and fox), ungulates (reindeer, European bison, moose), and man. Values at half the microwave power saturation of the radiation signal, P 1/2 , evaluated at room temperature, was found to range from 16 to 26 mW for animals and man. A new approach to discrimination of the radiation induced signal from the total ESR spectrum of reindeer enamel is proposed. ''Dose-response'' dependencies of enamel of different species mammals were measured within the dose range from 0.48 up to 10.08 Gy. Estimations of ''radiosensitivity'' enamel of carnivores and ungulates showed good agreement with radiosensitivity enamel of man by ESR method. (Author)

  11. A rugged and transferable method for determining blood cadmium, mercury, and lead with inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    McShane, William J.; Pappas, R. Steven; Wilson-McElprang, Veronica; Paschal, Dan

    2008-01-01

    A simple, high-throughput method for determining total cadmium, mercury, and lead in blood in cases of suspected exposure, using inductively coupled plasma-mass spectrometry (ICP-MS), has been developed and validated. One part matrix-matched standards, blanks, or aliquots of blood specimens were diluted with 49 parts of a solution containing 0.25% (w/w) tetramethylammonium hydroxide; 0.05% v/v Triton X-100 (blood cell membranes and protein solubilization); 0.01% (w/v) ammonium pyrolidinedithiocarbamate (mercury memory effect prevention and oxidation state stabilization, solubilization by complexation of all three metals); 1% v/v isopropanol (signal enhancement); and 10 μg/L iridium (internal standard). Thus the final dilution factor is 1 + 49. The method provides the basis for the determination of total cadmium, mercury, and lead for assessment of environmental, occupational, accidental ingestion or elevated exposures from other means. Approximately 80 specimens, including blanks, calibration standards, and quality control materials can be processed in an 8-h day. The method has been evaluated by examining reference materials from the National Institute of Standards and Technology, as well as by participation in six rounds of proficiency testing intercomparisons led by the Wadsworth Center of the New York State Department of Health. This method was developed for the purpose of increasing U.S. emergency response laboratory capacity. To this end, 33 U.S. state, and 1 district health department laboratories have validated this method in their own laboratories

  12. A rugged and transferable method for determining blood cadmium, mercury, and lead with inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McShane, William J. [Battelle-Centers for Disease Control and Prevention, Division of Laboratory Sciences, Emergency Response and Air Toxicants Branch, 4770 Buford Highway, MS F-44, Atlanta, GA 30341 (United States)], E-mail: WMcShane@cdc.gov; Pappas, R. Steven [Centers for Disease Control and Prevention, Division of Laboratory Sciences, Emergency Response and Air Toxicants, 4770 Buford Highway, MS F-44, Atlanta, GA 30341 (United States)], E-mail: RPappas@cdc.gov; Wilson-McElprang, Veronica [Battelle-Centers for Disease Control and Prevention, Division of Laboratory Sciences, Emergency Response and Air Toxicants Branch, 4770 Buford Highway, MS F-44, Atlanta, GA 30341 (United States)], E-mail: VWilsonMcelprang@cdc.gov; Paschal, Dan [Centers for Disease Control and Prevention, Division of Laboratory Sciences, Emergency Response and Air Toxicants, 4770 Buford Highway, MS F-44, Atlanta, GA 30341 (United States)], E-mail: DPaschal@cdc.gov

    2008-06-15

    A simple, high-throughput method for determining total cadmium, mercury, and lead in blood in cases of suspected exposure, using inductively coupled plasma-mass spectrometry (ICP-MS), has been developed and validated. One part matrix-matched standards, blanks, or aliquots of blood specimens were diluted with 49 parts of a solution containing 0.25% (w/w) tetramethylammonium hydroxide; 0.05% v/v Triton X-100 (blood cell membranes and protein solubilization); 0.01% (w/v) ammonium pyrolidinedithiocarbamate (mercury memory effect prevention and oxidation state stabilization, solubilization by complexation of all three metals); 1% v/v isopropanol (signal enhancement); and 10 {mu}g/L iridium (internal standard). Thus the final dilution factor is 1 + 49. The method provides the basis for the determination of total cadmium, mercury, and lead for assessment of environmental, occupational, accidental ingestion or elevated exposures from other means. Approximately 80 specimens, including blanks, calibration standards, and quality control materials can be processed in an 8-h day. The method has been evaluated by examining reference materials from the National Institute of Standards and Technology, as well as by participation in six rounds of proficiency testing intercomparisons led by the Wadsworth Center of the New York State Department of Health. This method was developed for the purpose of increasing U.S. emergency response laboratory capacity. To this end, 33 U.S. state, and 1 district health department laboratories have validated this method in their own laboratories.

  13. Development of an improved high resolution mass spectrometry based multi-residue method for veterinary drugs in various food matrices.

    Science.gov (United States)

    Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

    2011-08-26

    Multi-residue methods for veterinary drugs or pesticides in food are increasingly often based on ultra performance liquid chromatography (UPLC) coupled to high resolution mass spectrometry (HRMS). Previous available time of flight (TOF) technologies, showing resolutions up to 15,000 full width at half maximum (FWHM), were not sufficiently selective for monitoring low residue concentrations in difficult matrices (e.g. hormones in tissue or antibiotics in honey). The approach proposed in this paper is based on a single stage Orbitrap mass spectrometer operated at 50,000 FWHM. Extracts (liver and kidney) which were produced according to a validated multi-residue method (time of flight detection based) could not be analyzed by Orbitrap because of extensive signal suppression. This required the improvement of established extraction and clean-up procedures. The introduced, more extensive deproteinzation steps and dedicated instrumental settings successfully eliminated these detrimental suppression effects. The reported method, covering more than 100 different veterinary dugs, was validated according to the EU Commission Decision 2002/657/EEC. Validated matrices include muscle, kidney, liver, fish and honey. Significantly better performance parameters (e.g. linearity, reproducibility and detection limits) were obtained when comparing the new method with the older, TOF based method. These improvements are attributed to the higher resolution (50,000 versus 12,000 FWHM) and the superior mass stability of the of the Orbitrap over the previously utilized TOF instrument. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Absolute standardization of radionuclides with complex decay by the peak-sum coincidence method and photon spectrometry with HPGe detector

    International Nuclear Information System (INIS)

    Silva, Ronaldo Lins da

    2017-01-01

    This study aims to present a new methodology for absolute standardization of 133 Ba, which is a complex decay radionuclide, using the peak-sum coincidence method associated with gamma spectrometry with a high resolution germanium detector. The use of the method of direct multiplication of matrices allowed identifying all the energies of sum coincidence, as well as their probabilities of detection, which made possible the calculation of the probabilities of detecting the energies of interferences. In addition, with the use of deconvolution software it was possible to obtain the areas of energy without interference of other sums, and by means of the deduced equation for the peak sum method, it was possible to standardize 133 Ba. The result of the activity was compared with those found by the absolute methods existing in the LNMRI, where the result obtained by coincidence peak-sum was highlighted among all. The estimated uncertainties were below 0.30%, compatible with the results found in the literature by other absolute methods. Thus, it was verified that the methodology was able to standardize radionuclide 133 Ba with precision, accuracy, easiness and quickness. The relevance of this doctoral thesis is to provide the National Metrology Laboratory of Ionizing Radiation (LNMRI) with a new absolute standardization methodology for complex decay radionuclides. (author)

  15. Determination of thyroid hormones in mouse tissues by isotope-dilution microflow liquid chromatography-mass spectrometry method.

    Science.gov (United States)

    De Angelis, Meri; Giesert, Florian; Finan, Brian; Clemmensen, Christoffer; Müller, Timo D; Vogt-Weisenhorn, Daniela; Tschöp, Matthias H; Schramm, Karl-Werner

    2016-10-15

    Thyroid hormones (THs) play a critical role in the regulation of many biological processes such as growth, metabolism and development both in humans and wildlife. In general, TH levels are measured by immunoassay (IA) methods but the specificity of the antibodies used in these assays limits selectivity. In the last decade, several analytical methods using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS) have been developed to measure THs. These new techniques proved to be more accurate than the IA analysis and they were widely used for the determination of TH level in different human and animal tissues. A large part of LC-MS/MS methods described in literature employed between 200 and 500mg of sample, however this quantity can be considered too high especially when preclinical studies are conducted using mice as test subjects. Thus an analytical method that reduces the amount of tissue is essential. In this study, we developed a procedure for the analysis of six THs; L-thyroxine (T4), 3,3',5-triiodo-l-thyronine (T3), 3,3',5'-triiodo-l-thyronine (rT3), 3,5-diiodo-l-thyronine (rT2), 3,3'-diiodo-l-thyronine (T2), 3-iodo-l-thyronine (T1) using isotope ((13)C6-T4, (13)C6-T3, (13)C6-rT3, (13)C6-T2) dilution liquid chromatography-mass spectrometry. The major difference with previously described methods lies in the utilization of a nano-UPLC (Ultra Performance Liquid Chromatography) system in micro configuration. This approach leads to a reduction compared to the published methods, of column internal diameter, flow rate, and injected volume. The result of all these improvements is a decrease in the amount of sample necessary for the analysis. The method was tested on six different mouse tissues: liver, heart, kidney, muscle, lung and brown adipose tissue (BAT). The nano-UPLC system was interfaced with a quadrupole time-of-flight mass spectrometer (Q-TOF2-MS) using the positive ion mode electrospray ionization. In our analytical method

  16. Quantitative gas analysis with FT-IR

    DEFF Research Database (Denmark)

    Bak, J.; Larsen, A.

    1995-01-01

    Calibration spectra of CO in the 2.38-5100 ppm concentration range (22 spectra) have been measured with a spectral resolution of 4 cm(-1), in the mid-IR (2186-2001 cm(-1)) region, with a Fourier transform infrared (FT-IR) instrument. The multivariate calibration method partial least-squares (PLS1...

  17. Beta spectrometry

    International Nuclear Information System (INIS)

    Dryak, P.; Zderadicka, J.; Plch, J.; Kokta, L.; Novotna, P.

    1977-01-01

    For the purpose of beta spectrometry, a semiconductor spectrometer with one Si(Li) detector cooled with liquid nitrogen was designed. Geometrical detection efficiency is about 10% 4 sr. The achieved resolution for 624 keV conversion electrons of sup(137m)Ba is 2.6 keV (FWHM). A program was written in the FORTRAN language for the correction of the deformation of the measured spectra by backscattering in the analysis of continuous beta spectra. The method permits the determination of the maximum energy of the beta spectrum with an accuracy of +-5 keV. (author)

  18. IOT Overview: IR Instruments

    Science.gov (United States)

    Mason, E.

    In this instrument review chapter the calibration plans of ESO IR instruments are presented and briefly reviewed focusing, in particular, on the case of ISAAC, which has been the first IR instrument at VLT and whose calibration plan served as prototype for the coming instruments.

  19. Selective data reduction in gas chromatography/infrared spectrometry

    International Nuclear Information System (INIS)

    Pyo, Dong Jin; Shin, Hyun Du

    2001-01-01

    As gas chromatography/infrared spectrometry (GC/IR) becomes routinely available, methods must be developed to deal with the large amount of data produced. We demonstrate computer methods that quickly search through a large data file, locating those spectra that display a spectral feature of interest. Based on a modified library search routine, these selective data reduction methods retrieve all or nearly all of the compounds of interest, while rejection the vast majority of unrelated compounds. To overcome the shifting problem of IR spectra, a search method of moving the average pattern was designed. In this moving pattern search, the average pattern of a particular functional group was not held stationary, but was allowed to be moved a little bit right and left

  20. New method for determination of epichlorohydrin in epoxy-coated cans by oxolane derivatization and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Sung, Jun Hyun; Lee, Young Ja; Park, Hyun Jin

    2008-08-01

    A new method was developed for the determination of epichlorohydrin (ECH) in food contact surface of epoxy-coated cans. The oxolane derivative, which produced by reaction of epoxy moiety in ECH with cyclopentanone in the presence of borontrifluoride-diethyletherate, was analyzed by gas chromatography (GC)/mass spectrometry (MS). 1,2-Epoxyhexane was used as internal standard (IS), which produced an oxolane derivative under the same reaction mechanism as ECH. The developed method was validated with 1 ng ml(-1) of limit of detection (LOD, surface area related 20 ng dm(-2)), >0.999 of linearity. Good precision, which was tested both in terms of intra-day repeatability and inter-day reproducibility, and 97.3-102.7% of good recoveries were obtained on three spiked levels of 5.2, 40.3 and 149.1 ng ml(-1). The excellent validation data suggests that this method is more simple, quick and effective than the official method in European Committee for Standardization (CEN) to determine the residual amount of ECH in food contact materials for food law compliance test. The residual amount of ECH for 13 epoxy-coated can samples was analyzed, and none of the samples was found to be detectable levels of ECH in epoxy-coated cans.

  1. Toxic Cyanobacteria in Svalbard: Chemical Diversity of Microcystins Detected Using a Liquid Chromatography Mass Spectrometry Precursor Ion Screening Method

    Directory of Open Access Journals (Sweden)

    Julia Kleinteich

    2018-04-01

    Full Text Available Cyanobacteria synthesize a large variety of secondary metabolites including toxins. Microcystins (MCs with hepato- and neurotoxic potential are well studied in bloom-forming planktonic species of temperate and tropical regions. Cyanobacterial biofilms thriving in the polar regions have recently emerged as a rich source for cyanobacterial secondary metabolites including previously undescribed congeners of microcystin. However, detection and detailed identification of these compounds is difficult due to unusual sample matrices and structural congeners produced. We here report a time-efficient liquid chromatography-mass spectrometry (LC-MS precursor ion screening method that facilitates microcystin detection and identification. We applied this method to detect six different MC congeners in 8 out of 26 microbial mat samples of the Svalbard Archipelago in the Arctic. The congeners, of which [Asp3, ADMAdda5, Dhb7] MC-LR was most abundant, were similar to those reported in other polar habitats. Microcystins were also determined using an Adda-specific enzyme-linked immunosorbent assay (Adda-ELISA. Nostoc sp. was identified as a putative toxin producer using molecular methods that targeted 16S rRNA genes and genes involved in microcystin production. The mcy genes detected showed highest similarities to other Arctic or Antarctic sequences. The LC-MS precursor ion screening method could be useful for microcystin detection in unusual matrices such as benthic biofilms or lichen.

  2. Multiclass methods for the analysis of antibiotic residues in milk by liquid chromatography coupled to mass spectrometry: A review.

    Science.gov (United States)

    Rossi, Rosanna; Saluti, Giorgio; Moretti, Simone; Diamanti, Irene; Giusepponi, Danilo; Galarini, Roberta

    2018-02-01

    Milk is an important and beneficial food from a nutritional point of view, being an indispensable source of high quality proteins. Furthermore, it is a raw material for many dairy products, such as yoghurt, cheese, cream etc. Before reaching consumers, milk goes through production, processing and circulation. Each step involves potentially unsafe factors, such as chemical contamination that can affect milk quality. Antibiotics are widely used in veterinary medicine for dry cow therapy and mastitis treatment in lactating cows, which can cause the presence of antimicrobial residues in milk. In order to ensure consumers' safety, milk is analyzed to make sure that the fixed Maximum Residue Limits (MRLs) for antibiotics are not exceeded. Multiclass methods can monitor more drug classes through a single analysis, so they are faster, less time-consuming and cheaper than traditional methods (single-class); this aspect is particularly important for milk, which is a highly perishable food. Nevertheless, multiclass methods for veterinary drug residues in foodstuffs are real analytical challenges. This article reviews the major multiclass methods published for the determination of antibiotic residues in milk by liquid chromatography coupled to mass spectrometry, with a special focus on sample preparation approaches.

  3. [Multi-residue method for screening of pesticides in crops by liquid chromatography with tandem mass spectrometry].

    Science.gov (United States)

    Tanizawa, Haruna; Shima, Mikie; Ikehara, Chieko; Kobata, Masakazu; Sato, Motoaki

    2005-10-01

    A simple and rapid method was developed for the screening of 82 pesticides/metabolites in a wide variety of crops, using solid-phase extraction and liquid chromatography with tandem mass spectrometry (LC/MS/MS). After extraction with methanol, the filtered extracts were made up to 100 mL and a 2 mL aliquot was subjected to solid-phase extraction. Co-extractives were removed with a C18 mini-column, while pesticides were retained on 3 kinds of mini-columns (HLB, SAX, activated carbon), and then eluted with acetonitrile. Analysis was performed by LC/MS/MS, and MS acquisition parameters were established in positive and negative ESI modes. The utility of the method was demonstrated by the analysis of 6 crops (carrot, cabbage, onion, spinach, lemon, brown rice) and one mixed vegetable juice. Of 82 compounds tested, 75 in carrot and 62 in lemon were obtained with recoveries ranging from 70-120%. For all samples tested, 75 compounds could be obtained with recoveries of over 50%, and the detection limits of most compounds were lower than 0.01 microg/g. This method provides acceptable performance for analysis of these 75 compounds. Further, by using aliquots of the extracts with small-scale mini-columns, purified samples could be obtained. This proposed method with small matrix effects, is effective and suitable for screening of multiple residual pesticides by using LC/MS/MS.

  4. Determination of triacylglycerol regioisomers using electrospray ionization-quadrupole ion trap mass spectrometry with a kinetic method.

    Science.gov (United States)

    Leveque, Nathalie L; Acheampong, Akwasi; Heron, Sylvie; Tchapla, Alain

    2012-04-13

    The kinetic method was applied to differentiate and quantify mixtures of regioisomeric triacylglycerols (TAGs) by generating and mass selecting alkali ion bound metal dimeric clusters with a TAG chosen as reference (ref) and examining their competitive dissociations in a quadrupole ion trap mass spectrometer. This methodology readily distinguished pairs of regioisomers (AAB/ABA) such as LLO/LOL, OOP/OPO and SSP/SPS and consequently distinguished sn-1/sn-3, sn-2 substituents on the glycerol backbone. The dimeric complex ions [ref, Li, TAG((AAB and/or ABA))](+) generated by electrospray ionization mass spectrometry were subjected to collision induced dissociation causing competitive loss of either the neutral TAG reference (ref) leading to [Li(AAB and/or ABA)](+) or the neutral TAG molecule (TAG((AAB and/or ABA))) leading to [ref, Li](+). The ratio of the two competitive dissociation rates, defined by the product ion branching ratio (R(iso)), was related via the kinetic method to the regioisomeric composition of the investigated TAG mixture. In this work, a linear correlation was established between composition of the mixture of each TAG regioisomer and the logarithm of the branching ratio for competitive fragmentation. Depending on the availability of at least one TAG regioisomer as standard, the kinetic method and the standard additions method led to the quantitative analysis of natural TAG mixtures. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. A fast, comprehensive screening method for doping agents in urine by gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Van Eenoo, Peter; Van Gansbeke, Wim; De Brabanter, Nik; Deventer, Koen; Delbeke, Frans T

    2011-05-27

    The use of performance enhancing drugs in sports is prohibited. For the detection of misuse of such substances gas chromatography or liquid chromatography coupled to mass spectrometry are the most frequently used detection techniques. In this work the development and validation of a fast gas chromatography tandem mass spectrometric method for the detection of a wide range of doping agents is described. The method can determine 13 endogenous steroids (the steroid profile), 19-norandrosterone, salbutamol and 11-nor-Δ9-tetrahydrocannabinol.9carboxylic acid in the applicable ranges and to detect qualitatively over 140 substances in accordance with the minimum required performance levels of the World Anti-Doping Agency in 1ml of urine. The classes of substances included in the method are anabolic steroids, β2-agonists, stimulants, narcotics, hormone antagonists and modulators and beta-blockers. Moreover, using a short capillary column and hydrogen as a carrier gas the run time of the method is less than 8min. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Air and Surface Sampling Method for Assessing Exposures to Quaternary Ammonium Compounds Using Liquid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    LeBouf, Ryan F; Virji, Mohammed Abbas; Ranpara, Anand; Stefaniak, Aleksandr B

    2017-07-01

    This method was designed for sampling select quaternary ammonium (quat) compounds in air or on surfaces followed by analysis using ultraperformance liquid chromatography tandem mass spectrometry. Target quats were benzethonium chloride, didecyldimethylammonium bromide, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. For air sampling, polytetrafluoroethylene (PTFE) filters are recommended for 15-min to 24-hour sampling. For surface sampling, Pro-wipe® 880 (PW) media was chosen. Samples were extracted in 60:40 acetonitrile:0.1% formic acid for 1 hour on an orbital shaker. Method detection limits range from 0.3 to 2 ng/ml depending on media and analyte. Matrix effects of media are minimized through the use of multiple reaction monitoring versus selected ion recording. Upper confidence limits on accuracy meet the National Institute for Occupational Safety and Health 25% criterion for PTFE and PW media for all analytes. Using PTFE and PW analyzed with multiple reaction monitoring, the method quantifies levels among the different quats compounds with high precision (detection limits to capture quats on air sampling filters with only a 15-min sample duration with a maximum assessed storage time of 103 days before sample extraction. This method will support future exposure assessment and quantitative epidemiologic studies to explore exposure-response relationships and establish levels of quats exposures associated with adverse health effects. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  7. A new classification method for MALDI imaging mass spectrometry data acquired on formalin-fixed paraffin-embedded tissue samples.

    Science.gov (United States)

    Boskamp, Tobias; Lachmund, Delf; Oetjen, Janina; Cordero Hernandez, Yovany; Trede, Dennis; Maass, Peter; Casadonte, Rita; Kriegsmann, Jörg; Warth, Arne; Dienemann, Hendrik; Weichert, Wilko; Kriegsmann, Mark

    2017-07-01

    Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) shows a high potential for applications in histopathological diagnosis, and in particular for supporting tumor typing and subtyping. The development of such applications requires the extraction of spectral fingerprints that are relevant for the given tissue and the identification of biomarkers associated with these spectral patterns. We propose a novel data analysis method based on the extraction of characteristic spectral patterns (CSPs) that allow automated generation of classification models for spectral data. Formalin-fixed paraffin embedded (FFPE) tissue samples from N=445 patients assembled on 12 tissue microarrays were analyzed. The method was applied to discriminate primary lung and pancreatic cancer, as well as adenocarcinoma and squamous cell carcinoma of the lung. A classification accuracy of 100% and 82.8%, resp., could be achieved on core level, assessed by cross-validation. The method outperformed the more conventional classification method based on the extraction of individual m/z values in the first application, while achieving a comparable accuracy in the second. LC-MS/MS peptide identification demonstrated that the spectral features present in selected CSPs correspond to peptides relevant for the respective classification. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Mass Spectrometry Method to Measure Membrane Proteins in Dried Blood Spots for the Detection of Blood Doping Practices in Sport.

    Science.gov (United States)

    Cox, Holly D; Eichner, Daniel

    2017-09-19

    The dried blood spot (DBS) matrix has significant utility for applications in the field where venous blood collection and timely shipment of labile blood samples is difficult. Unfortunately, protein measurement in DBS is hindered by high abundance proteins and matrix interference that increases with hematocrit. We developed a DBS method to enrich for membrane proteins and remove soluble proteins and matrix interference. Following a wash in a series of buffers, the membrane proteins are digested with trypsin and quantitated by parallel reaction monitoring mass spectrometry methods. The DBS method was applied to the quantification of four cell-specific cluster of differentiation (CD) proteins used to count cells by flow cytometry, band 3 (CD233), CD71, CD45, and CD41. We demonstrate that the DBS method counts low abundance cell types such as immature reticulocytes as well as high abundance cell types such as red blood cells, white blood cells, and platelets. When tested in 82 individuals, counts obtained by the DBS method demonstrated good agreement with flow cytometry and automated hematology analyzers. Importantly, the method allows longitudinal monitoring of CD protein concentration and calculation of interindividual variation which is difficult by other methods. Interindividual variation of band 3 and CD45 was low, 6 and 8%, respectively, while variation of CD41 and CD71 was higher, 18 and 78%, respectively. Longitudinal measurement of CD71 concentration in DBS over an 8-week period demonstrated intraindividual variation 17.1-38.7%. Thus, the method may allow stable longitudinal measurement of blood parameters currently monitored to detect blood doping practices.

  9. Alternate method of source preparation for alpha spectrometry: No electrodeposition, no hydrofluoric acid

    International Nuclear Information System (INIS)

    Kurosaki, Hiromu; Mueller, Rebecca J.; Lambert, Susan B.; Rao, Govind R.

    2016-01-01

    An alternate method of preparing actinide alpha counting sources was developed in place of electrodeposition or lanthanide fluoride micro-precipitation. The method uses lanthanide hydroxide micro-precipitation to avoid the use of hazardous hydrofluoric acid. Lastly, it provides a quicker, simpler, and safer way of preparing actinide alpha counting sources in routine, production-type laboratories that process many samples daily.

  10. Alternate method of source preparation for alpha spectrometry: no electrodeposition, no hydrofluoric acid

    International Nuclear Information System (INIS)

    Hiromu Kurosaki; Lambert, S.B.; Rao, G.R.; Mueller, R.J.

    2017-01-01

    An alternate method of preparing actinide alpha counting sources was developed in place of electrodeposition or lanthanide fluoride micro-precipitation. The method uses lanthanide hydroxide micro-precipitation to avoid the use of hazardous hydrofluoric acid. It provides a quicker, simpler, and safer way of preparing actinide alpha counting sources in routine, production-type laboratories that process many samples daily. (author)

  11. A four dimensional separation method based on continuous heart-cutting gas chromatography with ion mobility and high resolution mass spectrometry.

    Science.gov (United States)

    Lipok, Christian; Hippler, Jörg; Schmitz, Oliver J

    2018-02-09

    A two-dimensional GC (2D-GC) method was developed and coupled to an ion mobility-high resolution mass spectrometer, which enables the separation of complex samples in four dimensions (2D-GC, ion mobilility spectrometry and mass spectrometry). This approach works as a continuous multiheart-cutting GC-system (GC+GC), using a long modulation time of 20s, which allows the complete transfer of most of the first dimension peaks to the second dimension column without fractionation, in comparison to comprehensive two-dimensional gas chromatography (GCxGC). Hence, each compound delivers only one peak in the second dimension, which simplifies the data handling even when ion mobility spectrometry as a third and mass spectrometry as a fourth dimension are introduced. The analysis of a plant extract from Calendula officinales shows the separation power of this four dimensional separation method. The introduction of ion mobility spectrometry provides an additional separation dimension and allows to determine collision cross sections (CCS) of the analytes as a further physicochemical constant supporting the identification. A CCS database with more than 800 standard substances including drug-like compounds and pesticides was used for CCS data base search in this work. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Peak Detection Method Evaluation for Ion Mobility Spectrometry by Using Machine Learning Approaches

    DEFF Research Database (Denmark)

    Hauschild, Anne-Christin; Kopczynski, Dominik; D'Addario, Marianna

    2013-01-01

    machine learning methods exist, an inevitable preprocessing step is reliable and robust peak detection without manual intervention. In this work we evaluate four state-of-the-art approaches for automated IMS-based peak detection: local maxima search, watershed transformation with IPHEx, region......-merging with VisualNow, and peak model estimation (PME).We manually generated Metabolites 2013, 3 278 a gold standard with the aid of a domain expert (manual) and compare the performance of the four peak calling methods with respect to two distinct criteria. We first utilize established machine learning methods...

  13. Efficient method of protein extraction from Theobroma cacao L. roots for two-dimensional gel electrophoresis and mass spectrometry analyses.

    Science.gov (United States)

    Bertolde, F Z; Almeida, A-A F; Silva, F A C; Oliveira, T M; Pirovani, C P

    2014-07-04

    Theobroma cacao is a woody and recalcitrant plant with a very high level of interfering compounds. Standard protocols for protein extraction were proposed for various types of samples, but the presence of interfering compounds in many samples prevented the isolation of proteins suitable for two-dimensional gel electrophoresis (2-DE). An efficient method to extract root proteins for 2-DE was established to overcome these problems. The main features of this protocol are: i) precipitation with trichloroacetic acid/acetone overnight to prepare the acetone dry powder (ADP), ii) several additional steps of sonication in the ADP preparation and extractions with dense sodium dodecyl sulfate and phenol, and iii) adding two stages of phenol extractions. Proteins were extracted from roots using this new protocol (Method B) and a protocol described in the literature for T. cacao leaves and meristems (Method A). Using these methods, we obtained a protein yield of about 0.7 and 2.5 mg per 1.0 g lyophilized root, and a total of 60 and 400 spots could be separated, respectively. Through Method B, it was possible to isolate high-quality protein and a high yield of roots from T. cacao for high-quality 2-DE gels. To demonstrate the quality of the extracted proteins from roots of T. cacao using Method B, several protein spots were cut from the 2-DE gels, analyzed by tandem mass spectrometry, and identified. Method B was further tested on Citrus roots, with a protein yield of about 2.7 mg per 1.0 g lyophilized root and 800 detected spots.

  14. A dilute-and-shoot flow-injection tandem mass spectrometry method for quantification of phenobarbital in urine.

    Science.gov (United States)

    Alagandula, Ravali; Zhou, Xiang; Guo, Baochuan

    2017-01-15

    Liquid chromatography/tandem mass spectrometry (LC/MS/MS) is the gold standard of urine drug testing. However, current LC-based methods are time consuming, limiting the throughput of MS-based testing and increasing the cost. This is particularly problematic for quantification of drugs such as phenobarbital, which is often analyzed in a separate run because they must be negatively ionized. This study examined the feasibility of using a dilute-and-shoot flow-injection method without LC separation to quantify drugs with phenobarbital as a model system. Briefly, a urine sample containing phenobarbital was first diluted by 10 times, followed by flow injection of the diluted sample to mass spectrometer. Quantification and detection of phenobarbital were achieved by an electrospray negative ionization MS/MS system operated in the multiple reaction monitoring (MRM) mode with the stable-isotope-labeled drug as internal standard. The dilute-and-shoot flow-injection method developed was linear with a dynamic range of 50-2000 ng/mL of phenobarbital and correlation coefficient > 0.9996. The coefficients of variation and relative errors for intra- and inter-assays at four quality control (QC) levels (50, 125, 445 and 1600 ng/mL) were 3.0% and 5.0%, respectively. The total run time to quantify one sample was 2 min, and the sensitivity and specificity of the method did not deteriorate even after 1200 consecutive injections. Our method can accurately and robustly quantify phenobarbital in urine without LC separation. Because of its 2 min run time, the method can process 720 samples per day. This feasibility study shows that the dilute-and-shoot flow-injection method can be a general way for fast analysis of drugs in urine. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  15. Fast methods for screening of trichothecenes in fungal cultures using gas chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Kristian Fog; Thrane, Ulf

    2001-01-01

    The paper presents a fast method for trichothecene profiling and chemotaxonomic studies in species of Fusarium, Stachybotrys, Trichoderma and Memnoniella. Micro scale extracted crude Fusarium extracts were derivatised using pentafluoropropionic anhydride and analysed by gas chromatography...

  16. Standard test method for radiochemical determination of uranium isotopes in urine by alpha spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 This test method is applicable to the determination of uranium in urine at levels of detection dependent on sample size, count time, detector background, and tracer yield. It is designed as a screening tool for detection of possible exposure of occupational workers. 1.2 This test method is designed for 50 mL of urine. This test method does not address the sampling protocol or sample preservation methods associated with its use. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  17. A deviation display method for visualising data in mobile gamma-ray spectrometry.

    OpenAIRE

    Kock, Peder; Finck, Robert R; Nilsson, Jonas M C; Östlund, Karl; Samuelsson, Christer

    2010-01-01

    A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called deviation display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded (137)Cs and (241)Am point sources and different natural background environments, the behaviour of the deviation displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPG...

  18. Methods for the analysis of overlapped peaks in analytical gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Sterlinski, S.; Wasek, M.

    1989-01-01

    A review of critical evaluation of simple methods for the analysis of overlapped peaks from the point of view of their applicability in activation analysis are described. These methods are adopted from other spectroscopic techniques and gas chromatography. The experimental verification has been carried out for gamma-ray spectra in the energy range 120 KeV - 3 MeV. 28 refs., 8 figs., 3 tabs. (author)

  19. Three rapid methods for determination 90Sr in milk samples using liquid scintillation spectrometry

    International Nuclear Information System (INIS)

    Abbasisiara, F.; Attarilar, N.; Afshar, N.

    2006-01-01

    Strontium radionuclide 90 Sr is one of the main long-lived components of the radioactive fallout which occurred as a result of previous atmospheric nuclear tests and also nuclear accidents such as Chernobyl accident. Due to chemical and biochemical similarities between strontium and calcium, more than 99% of strontium is efficiently incorporated into bone tissue and teeth and Characterized by along physical and biological half-life, it may cause damage to bone marrow. Since determination of this radionuclide often is a time consuming process, rapid determination methods specially in emergency situations is always desirable. In this work, three rapid methods for determination of this radionuclide in milk samples will be evaluated. All of the methods include two major steps: 1- strontium separation from fats and proteins which can be performed by drying (in case of the fresh milk samples), ashing and leaching by nitric acids or by using exchange or chelating resins which have strong affinity for alkaline earth cations such as Dowex 50W-X8. And 2- Separation of Sr-90 or its daughter product, Y-90. In two methods separation of 90 Sr is performed by extraction of the daughter nuclide, 90 Y, by aid of organic extracting agent, Tributylphosphate or T.B.P., and then Cherenkov counting of the Y-90 extracted. The third method is based on separation of this radionuclide using Crown Ether or Sr -Spec resin. The detailed radiochemical procedures and evaluation of each method advantages or disadvantages will explained in full text paper. (authors)

  20. Comparison of different sample preparation methods for platinum determination in cultured cells by graphite furnace atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Man Xiao

    2017-01-01

    Full Text Available Background Platinum-based agents are widely used in chemotherapy against solid tumors and insufficient intracellular drug accumulation is one of the leading causes of platinum resistance which is associated with poor survival of tumor patients. Thus, the detection of intracellular platinum is pivotal for studies aiming to overcome platinum resistance. In the present study, we aimed to establish a reliable graphite furnace atomic absorption spectrometry (GFAAS-based assay to quantify the intracellular platinum content for cultured cells. Methods Several most commonly applied cell preparation methods, including 0.2% HNO3, 0.2% Triton X-100, concentrated nitric acid, RIPA combined with concentrated nitric acid and hydroxide, followed by GFAAS for platinum detection were compared in ovarian, cervical and liver cancer cell lines to obtain the optimal one, and parameters regarding linearity, accuracy, precision and sensitivity were evaluated. Influence of other metals on platinum detection and the storage conditions of samples were also determined. Results The treatment of cells with 0.2% HNO3 was superior to other approaches with fewer platinum loss and better repeatability. The recovery rate and precision of this method were 97.3%–103.0% and 1.4%–3.8%, respectively. The average recoveries in the presence of other metals were 95.1%–103.1%. The detection limit was 13.23 ug/L. The recovery rate of platinum remained acceptable even in cell samples stored in −20 °C or −80 °C for two months. Discussion After comparison, we found that 0.2% HNO3 was optimal for intracellular platinum quantification based on GFAAS, which presented values compatible with that of inductively-coupled plasma mass-spectrometry (ICP-MS, and this is partially attributed to the simplicity of this method. Moreover, the assay was proved to be accurate, sensitive, cost-effective and suitable for the research of platinum-based antitumor therapy.

  1. A single-run liquid chromatography mass spectrometry method to quantify neuroactive kynurenine pathway metabolites in rat plasma.

    Science.gov (United States)

    Orsatti, Laura; Speziale, Roberto; Orsale, Maria Vittoria; Caretti, Fulvia; Veneziano, Maria; Zini, Matteo; Monteagudo, Edith; Lyons, Kathryn; Beconi, Maria; Chan, Kelvin; Herbst, Todd; Toledo-Sherman, Leticia; Munoz-Sanjuan, Ignacio; Bonelli, Fabio; Dominguez, Celia

    2015-03-25

    Neuroactive metabolites in the kynurenine pathway of tryptophan catabolism are associated with neurodegenerative disorders. Tryptophan is transported across the blood-brain barrier and converted via the kynurenine pathway to N-formyl-L-kynurenine, which is further degraded to L-kynurenine. This metabolite can then generate a group of metabolites called kynurenines, most of which have neuroactive properties. The association of tryptophan catabolic pathway alterations with various central nervous system (CNS) pathologies has raised interest in analytical methods to accurately quantify kynurenines in body fluids. We here describe a rapid and sensitive reverse-phase HPLC-MS/MS method to quantify L-kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxy-L-kynurenine (3HK) and anthranilic acid (AA) in rat plasma. Our goal was to quantify these metabolites in a single run; given their different physico-chemical properties, major efforts were devoted to develop a chromatography suitable for all metabolites that involves plasma protein precipitation with acetonitrile followed by chromatographic separation by C18 RP chromatography, detected by electrospray mass spectrometry. Quantitation range was 0.098-100 ng/ml for 3HK, 9.8-20,000 ng/ml for KYN, 0.49-1000 ng/ml for KYNA and AA. The method was linear (r>0.9963) and validation parameters were within acceptance range (calibration standards and QC accuracy within ±30%). Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Hydrophilic Interaction Liquid Chromatography/Mass Spectrometry: An Attractive and Prospective Method for the Quantitative Bioanalysis in Drug Metabolism.

    Science.gov (United States)

    Li, Zheng; Han, Jie; Sun, Shi-an; Chen, Kai; Tang, Dao-quan

    2016-01-01

    During the development, dosage optimization and safety evaluation of a drug, rapid and precise monitoring of administered drug and/or its metabolites in biological samples including blood, plasma, serum, tissues and saliva are vital. As drug biotransformation produces more hydrophilic metabolites for the enhancement of drug elimination, which is often a challenge for traditional reversed-phase liquid chromatography (RPLC) separation. Because hydrophilic interaction liquid chromatography (HILIC) is capable of retaining polar compounds and readily compatible with mass spectrometry (MS), HILIC has been used as a complementary separation technique to RPLC for analysis of polar metabolites, especially polar drugs and their metabolites. This review covers core aspects of HILIC-MS/MS method and overall profile of its application in analysis of drug and/or its metabolites. The emphasis of this paper has been placed on the applications of HILIC-MS/MS method in quantitative bioanalysis of drugs alone or along with their metabolites in drug metabolism studies in recent years. As a fundamental and critical step of bioanalytical method, conventional sample preparation techniques of biological matrices for the HILIC-MS/MS analysis of drugs and/or their metabolites are also briefly featured.

  3. Liquid Chromatography with Tandem Mass Spectrometry: A Sensitive Method for the Determination of Dehydrodiisoeugenol in Rat Cerebral Nuclei

    Directory of Open Access Journals (Sweden)

    You-Bo Zhang

    2016-03-01

    Full Text Available A new liquid chromatography–tandem mass spectrometry (LC-MS/MS method is developed for the quantification of dehydrodiisoeugenol (DDIE in rat cerebral nuclei after single intravenous administration. DDIE and daidzein (internal standard were separated on a Diamonsil™ ODS C18 column with methanol–water containing 0.1% formic acid (81:19, v/v as a mobile phase. Detection of DDIE was performed on a positive electrospray ionization source using a triple quadrupole mass spectrometer. DDIE and daidzein were monitored at m/z 327.2→188.0 and m/z 255.0→199.2, respectively, in multiple reaction monitoring mode. This method enabled quantification of DDIE in various brain areas, including, cortex, hippocampus, striatum, hypothalamus, cerebellum and brainstem, with high specificity, precision, accuracy, and recovery. The data herein demonstrate that our new LC-MS/MS method is highly sensitive and suitable for monitoring cerebral nuclei distribution of DDIE.

  4. Determining the Levels of Volatile Organic Pollutants in Urban Air Using a Gas Chromatography-Mass Spectrometry Method

    Science.gov (United States)

    Nicoara, Simona; Tonidandel, Loris; Traldi, Pietro; Watson, Jonathan; Morgan, Geraint; Popa, Ovidiu

    2009-01-01

    The paper presents the application of a method based on coupled gas chromatography-mass spectrometry, using an isotopically labelled internal standard for the quantitative analysis of benzene (B), toluene (T), ethyl benzene (E), and o-, m-, p-xylenes (X). Their atmospheric concentrations were determined based on short-term sampling, in different sites of Cluj-Napoca, a highly populated urban centre in N-W Romania, with numerous and diversified road vehicles with internal combustion engines. The method is relatively inexpensive and simple and shows good precision and linearity in the ranges of 7–60 μg/m3 (B), 13–90 μg/m3 (T), 7–50 μg/m3 (E), 10–70 μg/m3 (X-m,p), and 20–130 μg/m3 (X-o). The limits of quantitation/detection of the method LOQ/LOD are of 10/5 μg/m3 (Xo), 5/3 μg/m3 (B, E, X-m,p), and of 3/1 μg/m3 (T), respectively. PMID:20168976

  5. Determining the Levels of Volatile Organic Pollutants in Urban Air Using a Gas Chromatography-Mass Spectrometry Method

    Directory of Open Access Journals (Sweden)

    Simona Nicoara

    2009-01-01

    Full Text Available The paper presents the application of a method based on coupled gas chromatography-mass spectrometry, using an isotopically labelled internal standard for the quantitative analysis of benzene (B, toluene (T, ethyl benzene (E, and o-, m-, p-xylenes (X. Their atmospheric concentrations were determined based on short-term sampling, in different sites of Cluj-Napoca, a highly populated urban centre in N-W Romania, with numerous and diversified road vehicles with internal combustion engines. The method is relatively inexpensive and simple and shows good precision and linearity in the ranges of 7–60 μg/m3 (B, 13–90 μg/m3 (T, 7–50 μg/m3 (E, 10–70 μg/m3 (X-m,p, and 20–130 μg/m3 (X-o. The limits of quantitation/detection of the method LOQ/LOD are of 10/5 μg/m3 (Xo, 5/3 μg/m3 (B, E, X-m,p, and of 3/1 μg/m3 (T, respectively.

  6. Validation of a chiral liquid chromatography-tandem mass spectrometry method for the determination of pantoprazole in dog plasma.

    Science.gov (United States)

    Chen, Meixia; Xia, Yu; Ma, Zhiyu; Li, Liang; Zhong, Dafang; Chen, Xiaoyan

    2012-10-01

    Pantoprazole (PAN), a selective proton pump inhibitor, is used clinically as a racemic mixture for the treatment of acid-related gastrointestinal disorders. To investigate its stereoselective pharmacokinetics, a chiral liquid chromatography-tandem mass spectrometry method was developed and validated to determine the pantoprazole enantiomers in dog plasma. After liquid-liquid extraction, a baseline resolution of enantiomers was achieved on an ovomucoid column using the mobile phase of methanol:acetonitrile:10mM ammonium formate (pH 7) (10.4:2.6:87, v/v/v) at 30°C within 10min. Stable isotopically labeled (+)-d(3)-pantoprazole and (-)-d(3)-pantoprazole were used as internal standards. Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode via positive atmospheric pressure chemical ionization. The method was linear in the concentration range of 20.0-10,000ng/mL for each enantiomer using 25μL of dog plasma. The lower limit of quantification (LLOQ) for each enantiomer was 20.0ng/mL. Intra- and inter-day precision ranged from 3.2% to 10.3% for (+)-pantoprazole and 3.7-10.0% for (-)-pantoprazole. Accuracy varied from -1.4% to -0.2% for (+)-pantoprazole and -1.6% to 0.8% for (-)-pantoprazole. The validated method was applied successfully for stereoselective pharmacokinetic studies of racemic pantoprazole. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. A liquid chromatography with tandem mass spectrometry method for quantitating total and unbound ceritinib in patient plasma and brain tumor

    Directory of Open Access Journals (Sweden)

    Xun Bao

    2018-02-01

    Full Text Available A rapid, sensitive, and robust reversed-phase liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of total and unbound ceritinib, a second-generation ALK inhibitor, in patient plasma and brain tumor tissue samples. Sample preparation involved simple protein precipitation with acetonitrile. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C18 column using a 4-min gradient elution consisting of mobile phase A (0.1% formic acid in water and mobile phase B (0.1% formic acid in acetonitrile, at a flow rate of 0.4 mL/min. Ceritinib and the internal standard ([13C6]ceritinib were monitored using multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantitation (LLOQ was 1 nM of ceritinib in plasma. The calibration curve was linear over ceritinib concentration range of 1–2000 nM in plasma. The intra- and inter-day precision and accuracy were within the generally accepted criteria for bioanalytical method (<15%. The method was successfully applied to assess ceritinib brain tumor penetration, as assessed by the unbound drug brain concentration to unbound drug plasma concentration ratio, in patients with brain tumors.

  8. Application of radiochemical-and direct gamma ray spectrometry methods for the determination of the burnup of irradiated uranium oxide

    International Nuclear Information System (INIS)

    Cunha, I.I.L.; Nastasi, M.J.C.; Lima, F.W. de

    1979-01-01

    The burn-up of U 3 O 8 (natural uranium) samples was determined by using both destructive and non-destructive methods, and comparing the results obtained. The radioisotopes 144 Ce, 103 Ru, 106 Ru, 137 Cs and 95 Zr were chosen as monitors. In order to isolate the radioisotopes chosen as monitors, a separation scheme has been established in which the solvent extraction technic is used to separate cerium, cesium, and ruthenium one from the other and from uranium. The separation between zirconium and niobium and of both from the others was accomplished by means of adsorption on a silica-gel column. When the non-destructive method was used, the radioactivity of each nuclide of interest was measured in the presence of all others. For this purpose, use was made of gamma-ray spectrometry and a Ge-Li detector. The comparison of burn-up values obtained by both destructive and non-destructive methods was made by means of Student's 't' test, and it has shown that the averages of results obtained in each case are equal. (Author) [pt

  9. Challenges and opportunities of using liquid chromatography and mass spectrometry methods to develop complex vaccine antigens as pharmaceutical dosage forms.

    Science.gov (United States)

    Hickey, John M; Sahni, Neha; Toth, Ronald T; Kumru, Ozan S; Joshi, Sangeeta B; Middaugh, C Russell; Volkin, David B

    2016-10-01

    Liquid chromatographic methods, combined with mass spectrometry, offer exciting and important opportunities to better characterize complex vaccine antigens including recombinant proteins, virus-like particles, inactivated viruses, polysaccharides, and protein-polysaccharide conjugates. The current abilities and limitations of these physicochemical methods to complement traditional in vitro and in vivo vaccine potency assays are explored in this review through the use of illustrative case studies. Various applications of these state-of-the art techniques are illustrated that include the analysis of influenza vaccines (inactivated whole virus and recombinant hemagglutinin), virus-like particle vaccines (human papillomavirus and hepatitis B), and polysaccharide linked to protein carrier vaccines (pneumococcal). Examples of utilizing these analytical methods to characterize vaccine antigens in the presence of adjuvants, which are often included to boost immune responses as part of the final vaccine dosage form, are also presented. Some of the challenges of using chromatographic and LC-MS as physicochemical assays to routinely test complex vaccine antigens are also discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. SU-G-201-13: Investigation of Dose Variation Induced by HDR Ir-192 Source Global Shift Within the Varian Ring Applicator Using Monte Carlo Methods

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y; Cai, J; Meltsner, S; Chang, Z; Craciunescu, O [Duke University Medical Center, Durham, NC (United States)

    2016-06-15

    Purpose: The Varian tandem and ring applicators are used to deliver HDR Ir-192 brachytherapy for cervical cancer. The source path within the ring is hard to predict due to the larger interior ring lumen. Some studies showed the source could be several millimeters different from planned positions, while other studies demonstrated minimal dosimetric impact. A global shift can be applied to limit the effect of positioning offsets. The purpose of this study was to assess the necessities of implementing a global source shift using Monte Carlo (MC) simulations. Methods: The MCNP5 radiation transport code was used for all MC simulations. To accommodate TG-186 guidelines and eliminate inter-source attenuation, a BrachyVision plan with 10 dwell positions (0.5cm step sizes) was simulated as the summation of 10 individual sources with equal dwell times for simplification. To simplify the study, the tandem was also excluded from the MC model. Global shifts of ±0.1, ±0.3, ±0.5 cm were then simulated as distal and proximal from the reference positions. Dose was scored in water for all MC simulations and was normalized to 100% at the normalization point 0.5 cm from the cap in the ring plane. For dose comparison, Point A was 2 cm caudal from the buildup cap and 2 cm lateral on either side of the ring axis. With seventy simulations, 108 photon histories gave a statistical uncertainties (k=1) <2% for (0.1 cm)3 voxels. Results: Compared to no global shift, average Point A doses were 0.0%, 0.4%, and 2.2% higher for distal global shifts, and 0.4%, 2.8%, and 5.1% higher for proximal global shifts, respectively. The MC Point A doses differed by < 1% when compared to BrachyVision. Conclusion: Dose variations were not substantial for ±0.3 cm global shifts, which is common in clinical practice.

  11. SU-G-201-13: Investigation of Dose Variation Induced by HDR Ir-192 Source Global Shift Within the Varian Ring Applicator Using Monte Carlo Methods

    International Nuclear Information System (INIS)

    Yang, Y; Cai, J; Meltsner, S; Chang, Z; Craciunescu, O

    2016-01-01

    Purpose: The Varian tandem and ring applicators are used to deliver HDR Ir-192 brachytherapy for cervical cancer. The source path within the ring is hard to predict due to the larger interior ring lumen. Some studies showed the source could be several millimeters different from planned positions, while other studies demonstrated minimal dosimetric impact. A global shift can be applied to limit the effect of positioning offsets. The purpose of this study was to assess the necessities of implementing a global source shift using Monte Carlo (MC) simulations. Methods: The MCNP5 radiation transport code was used for all MC simulations. To accommodate TG-186 guidelines and eliminate inter-source attenuation, a BrachyVision plan with 10 dwell positions (0.5cm step sizes) was simulated as the summation of 10 individual sources with equal dwell times for simplification. To simplify the study, the tandem was also excluded from the MC model. Global shifts of ±0.1, ±0.3, ±0.5 cm were then simulated as distal and proximal from the reference positions. Dose was scored in water for all MC simulations and was normalized to 100% at the normalization point 0.5 cm from the cap in the ring plane. For dose comparison, Point A was 2 cm caudal from the buildup cap and 2 cm lateral on either side of the ring axis. With seventy simulations, 108 photon histories gave a statistical uncertainties (k=1) <2% for (0.1 cm)3 voxels. Results: Compared to no global shift, average Point A doses were 0.0%, 0.4%, and 2.2% higher for distal global shifts, and 0.4%, 2.8%, and 5.1% higher for proximal global shifts, respectively. The MC Point A doses differed by < 1% when compared to BrachyVision. Conclusion: Dose variations were not substantial for ±0.3 cm global shifts, which is common in clinical practice.

  12. Precise determination of sodium in serum by simulated isotope dilution method of inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Yan Ying; Zhang Chuanbao; Zhao Haijian; Chen Wenxiang; Shen Ziyu; Wang Xiaoru; Chen Dengyun

    2007-01-01

    A new precise and accurate method for the determination of sodium in serum by inductively coupled plasma mass spectrometry (ICP-MS) was developed. Since 23 Na is the single isotope element, 27 Al is selected as simulated isotope of Na. Al is spiked into serum samples and Na standard solution. 23 Na/ 27 Al ratio in the Na standard solution is determined to assume the natural Na isotope ratio. The serums samples are digested by purified HNO 3 /H 2 O 2 and diluted to get about 0.6 μg·g -1 Al solutions, and the 23 Na/ 27 Al ratios of the serum samples are obtained to calculate the accurate Na concentrations basing on the isotope dilution method. When the simulated isotope dilution method of ICP-MS is applied and Al is selected as the simulated isotope of Na, the precise and accurate Na concentrations in the serums are determined. The inter-day precision of CV<0.13% for one same serum sample is obtained during 3 days 4 measurements. The spike recoveries are between 99.69% and 100.60% for 4 different serum samples and 3 days multi-measurements. The results of measuring standard reference materials of serum sodium are agree with the certified value. The relative difference between 3 days is 0.22%-0.65%, and the relative difference in one bottle is 0.15%-0.44%. The ICP-MS and Al simulated isotope dilution method is proved to be not only precise and accurate, but also quick and convenient for measuring Na in serum. It is promising to be a reference method for precise determination of Na in serum. Since Al is a low cost isotope dilution reagent, the method is possible to be widely applied for serum Na determination. (authors)

  13. A Derivative Method with Free Radical Oxidation to Predict Resveratrol Metabolites by Tandem Mass Spectrometry.

    Science.gov (United States)

    Liu, Wangta; Shiue, Yow-Ling; Lin, Yi-Reng; Lin, Hugo You-Hsien; Liang, Shih-Shin

    2015-10-01

    In this study, we demonstrated an oxidative method with free radical to generate 3,5,4'-trihydroxy- trans -stilbene ( trans -resveratrol) metabolites and detect sequentially by an autosampler coupling with liquid chromatography electrospray ionization tandem mass spectrometer (LC-ESI-MS/MS). In this oxidative method, the free radical initiator, ammonium persulfate (APS), was placed in a sample bottle containing resveratrol to produce oxidative derivatives, and the reaction progress was tracked by autosampler sequencing. Resveratrol, a natural product with purported cancer preventative qualities, produces metabolites including dihydroresveratrol, 3,4'-dihydroxy- trans -stilbene, lunularin, resveratrol monosulfate, and dihydroresveratrol monosulfate by free radical oxidation. Using APS free radical, the concentrations of resveratrol derivatives differ as a function of time. Besides simple, convenient and time- and labor saving, the advantages of free radical oxidative method of its in situ generation of oxidative derivatives followed by LC-ESI-MS/MS can be utilized to evaluate different metabolites in various conditions.

  14. A deviation display method for visualising data in mobile gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kock, Peder, E-mail: Peder.Kock@med.lu.s [Department of Medical Radiation Physics, Clinical Sciences, Lund University, University Hospital, SE-221 85 Lund (Sweden); Finck, Robert R. [Swedish Radiation Protection Authority, SE-171 16 Stockholm (Sweden); Nilsson, Jonas M.C.; Ostlund, Karl; Samuelsson, Christer [Department of Medical Radiation Physics, Clinical Sciences, Lund University, University Hospital, SE-221 85 Lund (Sweden)

    2010-09-15

    A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called deviation display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded {sup 137}Cs and {sup 241}Am point sources and different natural background environments, the behaviour of the deviation displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPGe). The deviation display enhances positive significant changes while suppressing the natural background fluctuations. After an initialisation time of about 10 min this technique leads to a homogeneous display dominated by the background colour, where even small changes in spectral data are easy to discover. As this paper shows, the deviation display method works well for all tested gamma energies and natural background radiation levels and with both tested detector systems.

  15. A deviation display method for visualising data in mobile gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Kock, Peder; Finck, Robert R.; Nilsson, Jonas M.C.; Ostlund, Karl; Samuelsson, Christer

    2010-01-01

    A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called deviation display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded 137 Cs and 241 Am point sources and different natural background environments, the behaviour of the deviation displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPGe). The deviation display enhances positive significant changes while suppressing the natural background fluctuations. After an initialisation time of about 10 min this technique leads to a homogeneous display dominated by the background colour, where even small changes in spectral data are easy to discover. As this paper shows, the deviation display method works well for all tested gamma energies and natural background radiation levels and with both tested detector systems.

  16. Three rapid methods for determination {sup 90}Sr in milk samples using liquid scintillation spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Abbasisiara, F.; Attarilar, N. [Iranian Nuclear Regulatory Authority (INRA), Atomic Energy Organization of Iran (AEOI), Environmental Radiation Protection Div., National Radiation Protection Dept. (Iran, Islamic Republic of); Afshar, N. [Tarbiat Modarres Univ. (Iran, Islamic Republic of)

    2006-07-01

    Strontium radionuclide {sup 90}Sr is one of the main long-lived components of the radioactive fallout which occurred as a result of previous atmospheric nuclear tests and also nuclear accidents such as Chernobyl accident. Due to chemical and biochemical similarities between strontium and calcium, more than 99% of strontium is efficiently incorporated into bone tissue and teeth and Characterized by along physical and biological half-life, it may cause damage to bone marrow. Since determination of this radionuclide often is a time consuming process, rapid determination methods specially in emergency situations is always desirable. In this work, three rapid methods for determination of this radionuclide in milk samples will be evaluated. All of the methods include two major steps: 1- strontium separation from fats and proteins which can be performed by drying (in case of the fresh milk samples), ashing and leaching by nitric acids or by using exchange or chelating resins which have strong affinity for alkaline earth cations such as Dowex 50W-X8. And 2- Separation of Sr-90 or its daughter product, Y-90. In two methods separation of {sup 90}Sr is performed by extraction of the daughter nuclide, {sup 90}Y, by aid of organic extracting agent, Tributylphosphate or T.B.P., and then Cherenkov counting of the Y-90 extracted. The third method is based on separation of this radionuclide using Crown Ether or Sr -Spec resin. The detailed radiochemical procedures and evaluation of each method advantages or disadvantages will explained in full text paper. (authors)

  17. Method for the substantial reduction of quenching effects in luminescence spectrometry

    Science.gov (United States)

    Demas, J.N.; Jones, W.M.; Keller, R.A.

    1987-06-26

    Method for reducing quenching effects in analytical luminescence measurements. Two embodiments of the present invention are described which relate to a form of time resolution based on the amplitudes and phase shifts of modulated emission signals. In the first embodiment, the measured modulated emission signal is substantially independent of sample quenching at sufficiently high frequencies. In the second embodiment, the modulated amplitude and the phase shift between the emission signal and the excitation source are simultaneously measured. Using either method, the observed modulated amplitude may be reduced to its unquenched value. 3 figs.

  18. Determination of "1"2"9I using volatilization method and liquid scintillation spectrometry

    International Nuclear Information System (INIS)

    Remenec, Boris; Dulanska, Silvia; Horvathova, Bianka; Matel, Lubomir

    2017-01-01

    A simple and rapid separation method for "1"2"9I determination in radioactive waste samples was developed. Suitable conditions for iodine volatilization were tested. Iodine was trapped in 1.5 mol L"-"1 NaOH and precipitated as PdI_2·H_2O by addition of PdCl_2 with recoveries higher than 80%. The method was applied for analysis of contaminated soil, radioactive sludge, evaporator concentrate and heterogeneous waste samples from nuclear power plants in Slovak Republic. "1"2"9I was measured on liquid scintillation counter TRI CARB 2900 TR using Ultima Gold AB scintillation cocktail. (author)

  19. Simultaneous Detection of Androgen and Estrogen Abuse in Breeding Animals by Gas Chromatography-Mass Spectrometry/Combustion/Isotope Ratio Mass Spectrometry (GC-MS/C/IRMS) Evaluated against Alternative Methods.

    Science.gov (United States)

    Janssens, Geert; Mangelinckx, Sven; Courtheyn, Dirk; De Kimpe, Norbert; Matthijs, Bert; Le Bizec, Bruno

    2015-09-02

    The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring (13)C/(12)C isotopic ratios of their urinary metabolites. Gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) was used in this study to appraise in a global approach isotopic deviations of two 17β-testosterone metabolites (17α-testosterone and etiocholanolone) and one 17β-estradiol metabolite (17α-estradiol) together with those of 5-androstene-3β,17α-diol as endogenous reference compound (ERC). Intermediate precisions of 0.35‰, 1.05‰, 0.35‰, and 0.21‰, respectively, were observed (n = 8). To assess the performance of the analytical method, a bull and a heifer were treated with 17β-testosterone propionate and 17β-estradiol-3-benzoate. The sensitivity of the method permitted the demonstration of 17β-estradiol treatment up to 24 days. For 17β-testosterone treatment, the detection windows were 3 days and 24 days for the bull and the heifer, respectively. The capability of GC-MS/C/IRMS to demonstrate natural steroid abuse for urinary steroids was eventually compared to those of mass spectrometry (LC-MS/MS) when measuring intact steroid esters in blood and hair.

  20. A sensitive and selective liquid chromatography/tandem mass spectrometry method for quantitative analysis of efavirenz in human plasma.

    Directory of Open Access Journals (Sweden)

    Praveen Srivastava

    Full Text Available A selective and a highly sensitive method for the determination of the non-nucleoside reverse transcriptase inhibitor (NNRTI, efavirenz, in human plasma has been developed and fully validated based on high performance liquid chromatography tandem mass spectrometry (LC-MS/MS. Sample preparation involved protein precipitation followed by one to one dilution with water. The analyte, efavirenz was separated by high performance liquid chromatography and detected with tandem mass spectrometry in negative ionization mode with multiple reaction monitoring. Efavirenz and ¹³C₆-efavirenz (Internal Standard, respectively, were detected via the following MRM transitions: m/z 314.20243.90 and m/z 320.20249.90. A gradient program was used to elute the analytes using 0.1% formic acid in water and 0.1% formic acid in acetonitrile as mobile phase solvents, at a flow-rate of 0.3 mL/min. The total run time was 5 min and the retention times for the internal standard (¹³C₆-efavirenz and efavirenz was approximately 2.6 min. The calibration curves showed linearity (coefficient of regression, r>0.99 over the concentration range of 1.0-2,500 ng/mL. The intraday precision based on the standard deviation of replicates of lower limit of quantification (LLOQ was 9.24% and for quality control (QC samples ranged from 2.41% to 6.42% and with accuracy from 112% and 100-111% for LLOQ and QC samples. The inter day precision was 12.3% and 3.03-9.18% for LLOQ and quality controls samples, and the accuracy was 108% and 95.2-108% for LLOQ and QC samples. Stability studies showed that efavirenz was stable during the expected conditions for sample preparation and storage. The lower limit of quantification for efavirenz was 1 ng/mL. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully applied for therapeutic drug monitoring and pharmacokinetic studies in HIV-infected patients.

  1. Quantitative analysis of multiple high-resolution mass spectrometry images using chemometric methods: quantitation of chlordecone in mouse liver.

    Science.gov (United States)

    Mohammadi, Saeedeh; Parastar, Hadi

    2018-05-15

    In this work, a chemometrics-based strategy is developed for quantitative mass spectrometry imaging (MSI). In this regard, quantification of chlordecone as a carcinogenic organochlorinated pesticide (C10Cll0O) in mouse liver using the matrix-assisted laser desorption ionization MSI (MALDI-MSI) method is used as a case study. The MSI datasets corresponded to 1, 5 and 10 days of mouse exposure to the standard chlordecone in the quantity range of 0 to 450 μg g-1. The binning approach in the m/z direction is used to group high resolution m/z values and to reduce the big data size. To consider the effect of bin size on the quality of results, three different bin sizes of 0.25, 0.5 and 1.0 were chosen. Afterwards, three-way MSI data arrays (two spatial and one m/z dimensions) for seven standards and four unknown samples were column-wise augmented with m/z values as the common mode. Then, these datasets were analyzed using multivariate curve resolution-alternating least squares (MCR-ALS) using proper constraints. The resolved mass spectra were used for identification of chlordecone in the presence of a complex background and interference. Additionally, the augmented spatial profiles were post-processed and 2D images for each component were obtained in calibration and unknown samples. The sum of these profiles was utilized to set the calibration curve and to obtain the analytical figures of merit (AFOMs). Inspection of the results showed that the lower bin size (i.e., 0.25) provides more accurate results. Finally, the obtained results by MCR for three datasets were compared with those of gas chromatography-mass spectrometry (GC-MS) and MALDI-MSI. The results showed that the MCR-assisted method gives a higher amount of chlordecone than MALDI-MSI and a lower amount than GC-MS. It is concluded that a combination of chemometric methods with MSI can be considered as an alternative way for MSI quantification.

  2. Method Development for the Determination of Fluorotelomer Alcohols in Soils by Gas Chromatography Mass Spectrometry

    Science.gov (United States)

    Fluorotelomer alcohols (FTOHs) have been widely studied as precursors to perfluorocarboxylates, e.g. 8:2 FTOH degrades to perfluorooctanoic acid (PFOA). This presentation describes an analytical method for the extraction and analysis of 6:2, 8:2, and 10:2 FTOHs. Gas chromatograph...

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

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

  4. Determination of yields of gaseous products of carbohydrates radiolysis by mass spectrometry method. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Ivko, A A; Gol' din, S I; Bondarenko, N T; Markevich, S V; Sharpatii, V A [AN SSSR, Moscow. Inst. Khimicheskoj Fiziki

    1977-01-01

    Possible complications are treated involved in the mass spectral study of the radiolytic products of deuterated carbohydrates. A method is proposed suitable for the evaluation of hydrogen isotopes relations and the content of deuterium in water. It has been possible to identify the major gaseous radiolytic products of glucose, polyglucan and dextran, and also to assess their radiation-chemical yields.

  5. Determination of yields of gaseous products of carbohydrates radiolysis by mass spectrometry method

    International Nuclear Information System (INIS)

    Ivko, A.A.; Gol'din, S.I.; Bondarenko, N.T.; Markevich, S.V.; Sharpatyj, V.A.

    1977-01-01

    Possible complications are treated involved in the mass spectral study of the radiolytic products of deuterated carbohydrates. A method is proposed suitable for the evaluation of hydrogen isotopes relations and the content of deuterium in water. It has been possible to identify the major gaseous radiolytic products of glucose, polyglucan and dextran, and also to assess their radiation-chemical yields [ru

  6. Near infrared spectrometry for faecal fat measurement: comparison with conventional gravimetric and titrimetric methods.

    Science.gov (United States)

    Benini, L; Caliari, S; Guidi, G C; Vaona, B; Talamini, G; Vantini, I; Scuro, L A

    1989-01-01

    This investigation was aimed at comparing a new method for measuring faecal fat excretion, carried out with a semi-automated instrument by using near infrared analysis (NIRA), with the traditional titrimetric (Van de Kamer) and gravimetric (Sobel) methods. Near infrared analysis faecal fat was assayed on the three day stool collection from 118 patients (68 chronic pancreatitis, 19 organic diseases of the gastrointestinal tract, 19 alcoholic liver disease, 12 functional gastrointestinal disorders). A strict linear correlation was found between NIRA and both the titrimetric (r = 0.928, p less than 0.0001) and the gravimetric (r = 0.971, p less than 0.0001) methods. On homogenised faeces, a mean coefficient of variation of 2.1 (SD 1.71)% was found. Before homogenisation (where a mean coefficient of variation of 7% was found) accurate results were obtained when the mean of five measurements was considered. In conclusion, the assay of faecal fat excretion by the near infrared reflessometry appears a simple, rapid and reliable method for measuring steatorrhoea. PMID:2583563

  7. A liquid chromatography-mass spectrometry method for the quantification of bioavailability and bioconversion of beta-carotene to retinol in humans

    NARCIS (Netherlands)

    Yan Wang,; Xiaoying Xu,; Lieshout, van M.; West, C.E.; Lugtenburg, J.; Verhoeven, M.A.; Creemers, A.F.L.

    2000-01-01

    A method based on high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (APCI LC-MS) was developed for the quantification of the bioavailability of retinyl palmitate and -carotene and the bioconversion of -carotene to retinol in humans. Following oral

  8. A SIMPLE AND RAPID MATRIX-ASSISTED LASER DESORPTION/IONIZATION TIME OF FLIGHT MASS SPECTROMETRY METHOD TO SCREEN FISH PLASMA SAMPLES FOR ESTROGEN-RESPONSIVE BIOMARKERS

    Science.gov (United States)

    In this study, we describe and evaluate the performance of a simple and rapid mass spectral method for screening fish plasma for estrogen-responsive biomarkers using matrix assisted laster desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) couopled with a short...

  9. A validated liquid chromatography-tandem mass spectrometry method for the quantitative determination of 4 beta-hydroxycholesterol in human plasma

    NARCIS (Netherlands)

    van de Merbel, Nico C.; Bronsema, Kees J.; van Hout, Mischa W. J.; Nilsson, Ralf; Sillen, Henrik

    2011-01-01

    A novel liquid chromatography-tandem mass spectrometry method is described for the quantitative determination of the endogenous CYP 3A4/5 marker 4 beta-hydroxycholesterol in human K(2)-EDTA plasma. It is based on alkaline hydrolysis to convert esterified to free 4 beta-hydroxycholesterol, followed

  10. A gas chromatography-mass spectrometry (GC-MS) method for the detection and quantitation of monofluoroacetate in plants toxic to livestock

    Science.gov (United States)

    Monofluoroacetate (MFA) is a potent toxin that occurs in over 50 plant species in Africa, Australia, and South America and is responsible for significant livestock deaths in these regions. A gas chromatography–mass spectrometry (GC-MS) method for the analysis of MFA in plants based on the derivatiza...

  11. Determination of telmisartan in human blood plasma: Part II: Liquid chromatography-tandem mass spectrometry method development, comparison to immunoassay and pharmacokinetic study

    NARCIS (Netherlands)

    Hempen, C.M.; Gläsle-Schwarz, Liane; Kunz, Ulrich; Karst, U.

    2006-01-01

    A new liquid chromatography/atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI-MS/MS) method with on-line sample clean-up for the determination of telmisartan in human blood plasma is presented. This technique is compared to a previously introduced enzyme-linked immunosorbent

  12. Novel Selectivity-Based Forensic Toxicological Validation of a Paper Spray Mass Spectrometry Method for the Quantitative Determination of Eight Amphetamines in Whole Blood

    NARCIS (Netherlands)

    Teunissen, Sebastiaan F.; Fedick, Patrick W.; Berendsen, Bjorn J.A.; Nielen, Michel W.F.; Eberlin, Marcos N.; Graham Cooks, R.; Asten, van Arian C.

    2017-01-01

    Paper spray tandem mass spectrometry is used to identify and quantify eight individual amphetamines in whole blood in 1.3 min. The method has been optimized and fully validated according to forensic toxicology guidelines, for the quantification of amphetamine, methamphetamine,

  13. A method for studies on interactions between a gold-based drug and plasma proteins based on capillary electrophoresis with inductively coupled plasma mass spectrometry detection

    DEFF Research Database (Denmark)

    Nguyen, Tam T T N; Østergaard, Jesper; Gammelgaard, Bente

    2015-01-01

    An analytical method based on capillary electrophoresis (CE) and inductively coupled plasma mass spectrometry (ICP-MS) detection was developed for studies on the interaction of gold-containing drugs and plasma proteins using auranofin as example. A detection limit of 18 ng/mL of auranofin corresp...

  14. A rapid screening method to monitor expression of various recombinant proteins from prokaryotic and eukaryotic expression systems using MALDI-TOF mass spectrometry

    DEFF Research Database (Denmark)

    Jebanathirajah, J.A.; Andersen, S.; Blagoev, B.

    2002-01-01

    Rapid methods using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry to monitor recombinant protein expression from various prokaryotic and eukaryotic cell culture systems were devised. Intracellular as well as secreted proteins from both induced and constitutive...

  15. A novel method for analysing key corticosteroids in polar bear (Ursus maritimus) hair using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Weisser, Johan J; Hansen, Martin; Björklund, Erland; Sonne, Christian; Dietz, Rune; Styrishave, Bjarne

    2016-04-01

    This paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. Such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. We developed a combined pressurized liquid extraction (PLE)-solid phase extraction (SPE) procedure for corticosteroid extraction and clean-up followed by high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis. This procedure allows for the simultaneous determination of multiple steroids, which is in contrast to previous polar bear studies based on ELISA techniques. Absolute method recoveries were 81%, 75% and 60% for cortisol, corticosterone and aldosterone, respectively. We applied the developed method on a hair sample pooled from four East Greenland polar bears. Herein cortisol and corticosterone were successfully determined in levels of 0.32±0.02ng/g hair and 0.13±0.02ng/g hair, respectively. Aldosterone was below limit of detection (LODpolar bears was consistent with cortisol levels previously determined in the Southern Hudson Bay and James Bay in Canada using ELISA kits. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

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

  17. Automated correlation and classification of secondary ion mass spectrometry images using a k-means cluster method.

    Science.gov (United States)

    Konicek, Andrew R; Lefman, Jonathan; Szakal, Christopher

    2012-08-07

    We present a novel method for correlating and classifying ion-specific time-of-flight secondary ion mass spectrometry (ToF-SIMS) images within a multispectral dataset by grouping images with similar pixel intensity distributions. Binary centroid images are created by employing a k-means-based custom algorithm. Centroid images are compared to grayscale SIMS images using a newly developed correlation method that assigns the SIMS images to classes that have similar spatial (rather than spectral) patterns. Image features of both large and small spatial extent are identified without the need for image pre-processing, such as normalization or fixed-range mass-binning. A subsequent classification step tracks the class assignment of SIMS images over multiple iterations of increasing n classes per iteration, providing information about groups of images that have similar chemistry. Details are discussed while presenting data acquired with ToF-SIMS on a model sample of laser-printed inks. This approach can lead to the identification of distinct ion-specific chemistries for mass spectral imaging by ToF-SIMS, as well as matrix-assisted laser desorption ionization (MALDI), and desorption electrospray ionization (DESI).

  18. Chiral liquid chromatography-mass spectrometry (LC-MS/MS) method development for the detection of salbutamol in urine samples.

    Science.gov (United States)

    Chan, Sue Hay; Lee, Warren; Asmawi, Mohd Zaini; Tan, Soo Choon

    2016-07-01

    A sequential solid-phase extraction (SPE) method was developed and validated using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the detection and quantification of salbutamol enantiomers in porcine urine. Porcine urine samples were hydrolysed with β-glucuronidase/arylsulfatase from Helix pomatia and then subjected to a double solid-phase extraction (SPE) first using the Abs-Elut Nexus SPE and then followed by the Bond Elut Phenylboronic Acid (PBA) SPE. The salbutamol enantiomers were separated using the Astec CHIROBIOTIC™ T HPLC column (3.0mm×100mm; 5μm) maintained at 15°C with a 15min isocratic run at a flow rate of 0.4mL/min. The mobile phase constituted of 5mM ammonium formate in methanol. Salbutamol and salbutamol-tert-butyl-d9 (internal standard, IS) was monitored and quantified with the multiple reaction monitoring (MRM) mode. The method showed good linearity for the range of 0.1-10ng/mL with limit of quantification at 0.3ng/mL. Analysis of the QC samples showed intra- and inter-assay precisions to be less than 5.04%, and recovery ranging from 83.82 to 102.33%. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Development of Extraction Methods for the Analysis of Perfluorinated Compounds in Leather with High Performance Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Zhang, Yan; Wang, Youchao; Tang, Chuanjiang; Nie, Jingmei; Xu, Chengtao

    2018-01-01

    Perfluorinated compounds (PFCs), used to provide water, oil, grease, heat and stain repellency to a range of textile and other products, have been found to be persistent in the environment and are associated with adverse effects on humans and wildlife. This study presents the development and validation of an analytical method to determine the simultaneous presence of eleven PFCs in leather using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The perfluorinated compounds were primarily extracted from the samples by a liquid extraction procedure by ultrasonic, in which the parameters were optimized. Then the solid-phase extraction (SPE) is the most important advantages of the developed methodology. The sample volume and elution conditions were optimized by means of an experimental design. The proposed method was applied to determine the PFCs in leather, where the detection limits of the eleven compounds were 0.09-0.96 ng/L, and the recoveries of all compounds spiked at 5 ng/L concentration level were in the range of 65-96%, with a better RSD lower than 19% (n = 7).

  20. Liquid chromatography – tandem mass spectrometry method for the determination of ten tetracycline residues in muscle samples

    Directory of Open Access Journals (Sweden)

    Gajda Anna

    2015-09-01

    Full Text Available A liquid chromatography – tandem mass spectrometry (LC-MS/MS method for the determination of oxytetracycline (OTC, 4-epi oxytetracycline (4-epi OTC, tetracycline (TC, 4-epi tetracycline (4-epi TC, chlortetracycline (CTC, 4-epi chlortetracycline (4-epi CTC, doxycycline (DC, minocycline (MINO, methacycline (META and rolitetracycline (ROLI residues in muscles was developed. The procedure consisted of an oxalic acid extraction followed by protein removal with trichloroacetic acid. Further solid phase clean-up on polymeric (Strata X reversed phase columns was performed to obtain an extract suitable for LC-MS/MS analysis. The tetracyclines were separated on a C 18 analytical column with mobile phase consisting of 0.01% formic acid in acetonitrile and 0.01% formic acid in water in gradient mode. The method was validated according to the Commission Decision 2002/657/EC. The recoveries of all target compounds were 91.8% – 103.6%. The decision limits were from 109.0 to 119.8 μg/kg and detection capability varied within the range of 122.2 to 137.6 μg/kg, depending on the analyte.

  1. A sediment extraction and cleanup method for wide-scope multitarget screening by liquid chromatography-high-resolution mass spectrometry.

    Science.gov (United States)

    Massei, Riccardo; Byers, Harry; Beckers, Liza-Marie; Prothmann, Jens; Brack, Werner; Schulze, Tobias; Krauss, Martin

    2018-01-01

    Previous studies on organic sediment contaminants focused mainly on a limited number of highly hydrophobic micropollutants accessible to gas chromatography using nonpolar, aprotic extraction solvents. The development of liquid chromatography-high-resolution mass spectrometry (LC-HRMS) permits the spectrum of analysis to be expanded to a wider range of more polar and ionic compounds present in sediments and allows target, suspect, and nontarget screening to be conducted with high sensitivity and selectivity. In this study, we propose a comprehensive multitarget extraction and sample preparation method for characterization of sediment pollution covering a broad range of physicochemical properties that is suitable for LC-HRMS screening analysis. We optimized pressurized liquid extraction, cleanup, and sample dilution for a target list of 310 compounds. Finally, the method was tested on sediment samples from a small river and its tributaries. The results show that the combination of 100 °C for ethyl acetate-acetone (50:50, neutral extract) followed by 80 °C for acetone-formic acid (100:1, acidic extract) and methanol-10 mM sodium tetraborate in water (90:10, basic extract) offered the best extraction recoveries for 287 of 310 compounds. At a spiking level of 1 μg mL -1 , we obtained satisfactory cleanup recoveries for the neutral extract-(93 ± 23)%-and for the combined acidic/basic extracts-(42 ± 16)%-after solvent exchange. Among the 69 compounds detected in environmental samples, we successfully quantified several pharmaceuticals and polar pesticides.

  2. Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy as an Analytical Method to Investigate the Secondary Structure of a Model Protein Embedded in Solid Lipid Matrices.

    Science.gov (United States)

    Zeeshan, Farrukh; Tabbassum, Misbah; Jorgensen, Lene; Medlicott, Natalie J

    2018-02-01

    Protein drugs may encounter conformational perturbations during the formulation processing of lipid-based solid dosage forms. In aqueous protein solutions, attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy can investigate these conformational changes following the subtraction of spectral interference of solvent with protein amide I bands. However, in solid dosage forms, the possible spectral contribution of lipid carriers to protein amide I band may be an obstacle to determine conformational alterations. The objective of this study was to develop an ATR FT-IR spectroscopic method for the analysis of protein secondary structure embedded in solid lipid matrices. Bovine serum albumin (BSA) was chosen as a model protein, while Precirol AT05 (glycerol palmitostearate, melting point 58 ℃) was employed as the model lipid matrix. Bovine serum albumin was incorporated into lipid using physical mixing, melting and mixing, or wet granulation mixing methods. Attenuated total reflection FT-IR spectroscopy and size exclusion chromatography (SEC) were performed for the analysis of BSA secondary structure and its dissolution in aqueous media, respectively. The results showed significant interference of Precirol ATO5 with BSA amide I band which was subtracted up to 90% w/w lipid content to analyze BSA secondary structure. In addition, ATR FT-IR spectroscopy also detected thermally denatured BSA solid alone and in the presence of lipid matrix indicating its suitability for the detection of denatured protein solids in lipid matrices. Despite being in the solid state, conformational changes occurred to BSA upon incorporation into solid lipid matrices. However, the extent of these conformational alterations was found to be dependent on the mixing method employed as indicated by area overlap calculations. For instance, the melting and mixing method imparted negligible effect on BSA secondary structure, whereas the wet granulation mixing method promoted

  3. Reproduction of the coincidence effect in gamma ray spectrometry by using Monte Carlo method

    International Nuclear Information System (INIS)

    Park, S. H.; Kim, J. K.; Lee, S. H.

    2001-01-01

    Scintillation detector such as NaI(TI), or semiconductor detector, such as HPGe, are used for Measurement/Assessment of the radiation type and radiation activity. The measured energy spectrum are used for measuring the radiation type and activity. Corrections for true coincidence due to emit more than 2 photons at the same time and random coincidence due to measuring system when increasing of the radiation intensity. For accurate assessment, measurement with adequate measure system is performed, and corrections for coincidence are performed in the hardware aspect and software aspect. In general, there are limitations or difficulties in measurement of radiation assessment, computational simulation is instead used. In simulation, it has much advantages than measurement in technically, timely, and financially, it is widely used instead of measurement. In this study, the method to reproduce of the coincidence effect was proposed by using monte carlo method

  4. Method for 236U Determination in Seawater Using Flow Injection Extraction Chromatography and Accelerator Mass Spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter

    2015-01-01

    An automated analytical method implemented in a flow injection (FI) system was developed for rapid determination of 236U in 10 L seawater samples. 238U was used as a chemical yield tracer for the whole procedure, in which extraction chromatography (UTEVA) was exploited to purify uranium, after...... experimental parameters affecting the analytical effectiveness were investigated and optimized in order to achieve high chemical yields and simple and rapid analysis as well as low procedure background. Besides, the operational conditions for the target preparation prior to the AMS measurement were optimized......, on the basis of studying the coprecipitation behavior of uranium with iron hydroxide. The analytical results indicate that the developed method is simple and robust, providing satisfactory chemical yields (80−100%) and high analysis speed (4 h/sample), which could be an appealing alternative to conventional...

  5. An electrodeposition method for the preparation of actinides and Ra samples for α spectrometry

    International Nuclear Information System (INIS)

    Garcia-Tenorio, R.; Garcia-Leon, M.; Madurga, G.; Piazza, C.

    1986-01-01

    As it is confirmed in this work, electrodeposition of α radionuclides gives a simple method for preparing α samples of high spectrometric quality, compared to those prepared by evaporation. Then we give the methods for electrodepositon or α emitters use in our Department. Actinides α emitters are electroplated from a 1% H 2 SO 4 medium with a recovery of about 90%. The samples of Ra are prepared by electrodeposition from a HCl + CH 3 -COONH 4 medium at pH approx.= 5. In this case the recovery reaches a value that ranges from 70 to 90%. For these measurements a Si surface barrier detector has been used. Some of its features are discussed in the text. (author)

  6. Mass spectrometry-based methods for detection and differentiation of botulinum neurotoxins

    Science.gov (United States)

    Schmidt, Jurgen G [Los Alamos, NM; Boyer, Anne E [Atlanta, GA; Kalb, Suzanne R [Atlanta, GA; Moura, Hercules [Tucker, GA; Barr, John R [Suwannee, GA; Woolfitt, Adrian R [Atlanta, GA

    2009-11-03

    The present invention is directed to a method for detecting the presence of clostridial neurotoxins in a sample by mixing a sample with a peptide that can serve as a substrate for proteolytic activity of a clostridial neurotoxin; and measuring for proteolytic activity of a clostridial neurotoxin by a mass spectroscopy technique. In one embodiment, the peptide can have an affinity tag attached at two or more sites.

  7. Method Optimization for Rapid Measurement of Carbohydrates in Plasma by Liquid Chromatography Tandem Mass Spectrometry

    International Nuclear Information System (INIS)

    Nguyen, Ductoan; Yu, Jondong; Mho, Sunil; Lee, Gwang; Lee, Haelee; Paik, Manjeong; Yee, Sungtae

    2013-01-01

    In conclusion, the developed HPLC coupled with ESI-MS was a powerful technique for the separation and characterization of carbohydrates by either SIM or MRM mode. The present method will be useful for the monitoring of carbohydrate profile in biological fluids from various diseases including diabetic ketoacidosis, hypoglycemia and hyperosmolar coma. Carbohydrates are one of the most abundant classes of organic compounds in nature, which not only constitute complex biomolecules in human and animals but are also distributed in plants and bacteria

  8. ENVIRONMENTAL ANALYSIS BY AB INITIO QUANTUM MECHANICAL COMPUTATION AND GAS CHROMATOGRAPHY/FOURIER TRANSFORM INFRARED SPECTROMETRY.

    Science.gov (United States)

    Computational chemistry, in conjunction with gas chromatography/mass spectrometry/Fourier transform infrared spectrometry (GC/MS/FT-IR), was used to tentatively identify seven tetrachlorobutadiene (TCBD) isomers detected in an environmental sample. Computation of the TCBD infrare...

  9. A novel FT-IR spectroscopic method based on lipid characteristics for qualitative and quantitative analysis of animal-derived feedstuff adulterated with ruminant ingredients.

    Science.gov (United States)

    Gao, Fei; Zhou, Simiao; Han, Lujia; Yang, Zengling; Liu, Xian

    2017-12-15

    The objective of this study was to explore the ability of Fourier transform infrared (FT-IR) spectroscopy to authenticate adulterated animal-derived feedstuff. A total of 18 raw meat and bone meals (MBMs), including 9 non-ruminant MBMs and 9 ruminant MBMs, were mixed to obtain 81 binary mixtures with specific proportions (1-35%). Lipid spectral characteristics were analyzed by FT-IR spectroscopy combined with chemometrics. Changes in FT-IR spectra were observed as adulterant concentration was varied. The results illustrate ruminant adulteration can be successfully distinguished based on lipid characteristics. PLS model was established to quantify ruminant adulteration, which was shown to be valid (R 2 P >0.90). Furthermore, the ratios of CC/CO and CC/CH(CH 2 ), as well as the number of CH(CH 2 ) in the fatty acids of adulterated lipids, were calculated, which showed that differences in the trans fatty acid content and the degree of unsaturation were the main contributors to determination of adulteration based on FT-IR spectroscopy. Copyright © 2017. Published by Elsevier Ltd.

  10. Molecular structure, vibrational spectroscopic analysis (IR & Raman), HOMO-LUMO and NBO analysis of anti-cancer drug sunitinib using DFT method

    Science.gov (United States)

    Mıhçıokur, Özlem; Özpozan, Talat

    2017-12-01

    Oxindole and its derivatives have wide applications in different industries such as in synthetic & natural fibers, dyes for hair and plastic materials in addition to their biological importance. In the present study, one of the oxindole derivatives, N-(2-diethylaminoethyl)-5-[(Z)-(5-fluoro-2-oxo-1H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide (Sunitinib), which is used as an anti-cancer drug, was investigated in terms of structural, vibrational spectroscopic and theoretical analysis. The calculations have been performed for gaseous, aqueous and DMSO phases, respectively. Potential Energy Surface (PES) scan has been carrried out to obtain the most stable structures of all the phases of the title molecule using B3LYP/6-31G(d,p) level and the geometrical variations among them are discussed. The solvent effect for Sunitinib in aqueous and DMSO phases have been performed by means of the self-consistent recognition reaction field (SCRF) method as implemented in the integral equation formalism polarized continuum model (IEFPCM). On the other hand, NBO analysis has been carried out to understand probable hydrogen bonding sites and charge transfers. Additionally, the HOMO and the LUMO energies are calculated using B3LYP/6-31G(d,p) to determine the intra molecular charge transfers (ICT) within the molecule and the kinetic stabilities for each phases. The molecular electrostatic potential surface (MESP) has been plotted over the optimized structure to estimate the reactive sites of electrophilic and nucleophilic attacks regarding Sunitinib molecule. The potential energy distribution (PED) has been calculated using VEDA4 program and vibrational assignments of the experimental spectra (IR & Raman) have been elucidated by means of the calculated vibrational spectra. The observed vibrational spectra of Sunitinib is compared with the calculated spectra obtained by using B3LYP functional both with 6-31G(d,p) and 6-311++G(d,p) basis sets. Theoretical results

  11. A rapid method for simultaneous determination of arsenic, cadmium and lead in drinking water by inductively coupled plasma mass spectrometry

    Directory of Open Access Journals (Sweden)

    Joshua Rey P. Torres

    Full Text Available The raw water source of drinking water in most areas in the Philippines is typically river water and in some cases groundwater. These sources are prone to elevated levels of metals and metalloids that may cause exposure of the general population when the treatment of the water is inadequate. This work presents a simple method based on EPA Method 200.8 for the determination of total concentrations of arsenic (As, cadmium (Cd and lead (Pb in drinking water using inductively coupled plasma-mass spectrometry (ICP-MS as the element-selective detector. This was applied in the determination of these elements in the water supply in Metro Manila, Philippines. The method detection limits were 0.095 μg L-1, 0.043 μg L-1, and 0.114 μg L-1 for total As, Cd and Pb, respectively.The method was validated using National Institute of Standards and Technology (NIST 1643e certified reference material for trace elements in water and determined values were 60.4 ± 0.5 μg L-1, 6.7 ± 0.1 μg L-1, and 19.6 ± 0.5 μg L-1 for As, Cd and Pb, respectively. These determined values were in good agreement with the certified values in the reference material. Analysis of actual drinking water samples showed that most samples did not exceed the limit of the Philippine drinking water standard for the elements.

  12. Validation of the doubly labeled water method using off-axis integrated cavity output spectroscopy and isotope ratio mass spectrometry.

    Science.gov (United States)

    Melanson, Edward L; Swibas, Tracy; Kohrt, Wendy M; Catenacci, Vicki A; Creasy, Seth A; Plasqui, Guy; Wouters, Loek; Speakman, John R; Berman, Elena S F

    2018-02-01

    When the doubly labeled water (DLW) method is used to measure total daily energy expenditure (TDEE), isotope measurements are typically performed using isotope ratio mass spectrometry (IRMS). New technologies, such as off-axis integrated cavity output spectroscopy (OA-ICOS) provide comparable isotopic measurements of standard waters and human urine samples, but the accuracy of carbon dioxide production (V̇co 2 ) determined with OA-ICOS has not been demonstrated. We compared simultaneous measurement V̇co 2 obtained using whole-room indirect calorimetry (IC) with DLW-based measurements from IRMS and OA-ICOS. Seventeen subjects (10 female; 22 to 63 yr) were studied for 7 consecutive days in the IC. Subjects consumed a dose of 0.25 g H 2 18 O (98% APE) and 0.14 g 2 H 2 O (99.8% APE) per kilogram of total body water, and urine samples were obtained on days 1 and 8 to measure average daily V̇co 2 using OA-ICOS and IRMS. V̇co 2 was calculated using both the plateau and intercept methods. There were no differences in V̇co 2 measured by OA-ICOS or IRMS compared with IC when the plateau method was used. When the intercept method was used, V̇co 2 using OA-ICOS did not differ from IC, but V̇co 2 measured using IRMS was significantly lower than IC. Accuracy (~1-5%), precision (~8%), intraclass correlation coefficients ( R = 0.87-90), and root mean squared error (30-40 liters/day) of V̇co 2 measured by OA-ICOS and IRMS were similar. Both OA-ICOS and IRMS produced measurements of V̇co 2 with comparable accuracy and precision compared with IC.

  13. [Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry].

    Science.gov (United States)

    Shang, Xiaohong; Zhao, Yunfeng; Zhang, Lei; Li, Xiaowei; Wu, Yongning

    2011-07-01

    The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry (LC-CV-AFS). Cysteine was used as complexing agent in mobile phase instead of mercaptoethanol. Under the optimized conditions, baseline separation of mercury species could be achieved within 8 min on a C18 column with a mobile phase of 5% (v/v) acetonitrile-1 g/L L-cysteine-50 mmol/L ammonium acetate aqueous solution. The linear range of calibration curve of methylmercury was 1-50 microg/L and the limit of detection (S/N = 3) for methylmercury was 0.3 microg/L. Ultrasonication assisted hydrochloric acid extraction was used to extract methylmercury from seafood samples. The sample extract was cleaned up by a C18 solid phase extraction (SPE) cartridge. For validation of the method, certified reference materials and spiked seafood samples were analyzed. The determined methylmercury contents of certified reference materials NIST1566b, BCR464 and GBW10029 agreed well with the certified values. The determined methylmercury values for Food Analysis Performance Assessment Scheme (FAPAS) sample 07115 were satisfied. The recoveries of methylmercury in seafood samples at three spiked levels (10, 50 and 500 microg/kg) ranged from 89% to 112%, including cooked seafood food. The precision of the method based on relative standard deviation (RSD) was not more than 7%. The present method of LC-CV-AFS is accurate, sensitive, simple, and can meet the demand of methylmercury determination in seafood.

  14. PKCδ-mediated IRS-1 Ser24 phosphorylation negatively regulates IRS-1 function

    International Nuclear Information System (INIS)

    Greene, Michael W.; Ruhoff, Mary S.; Roth, Richard A.; Kim, Jeong-a; Quon, Michael J.; Krause, Jean A.

    2006-01-01

    The IRS-1 PH and PTB domains are essential for insulin-stimulated IRS-1 Tyr phosphorylation and insulin signaling, while Ser/Thr phosphorylation of IRS-1 disrupts these signaling events. To investigate consensus PKC phosphorylation sites in the PH-PTB domains of human IRS-1, we changed Ser24, Ser58, and Thr191 to Ala (3A) or Glu (3E), to block or mimic phosphorylation, respectively. The 3A mutant abrogated the inhibitory effect of PKCδ on insulin-stimulated IRS-1 Tyr phosphorylation, while reductions in insulin-stimulated IRS-1 Tyr phosphorylation, cellular proliferation, and Akt activation were observed with the 3E mutant. When single Glu mutants were tested, the Ser24 to Glu mutant had the greatest inhibitory effect on insulin-stimulated IRS-1 Tyr phosphorylation. PKCδ-mediated IRS-1 Ser24 phosphorylation was confirmed in cells with PKCδ catalytic domain mutants and by an RNAi method. Mechanistic studies revealed that IRS-1 with Ala and Glu point mutations at Ser24 impaired phosphatidylinositol-4,5-bisphosphate binding. In summary, our data are consistent with the hypothesis that Ser24 is a negative regulatory phosphorylation site in IRS-1

  15. RESEARCH OF SOPHORA JAPONICA L. FLOWER BUDS VOLATILE COMPOUNDS WITH GAS-CHROMATOGRAPHY/MASS- SPECTROMETRY METHOD

    Directory of Open Access Journals (Sweden)

    Cholak I.S.

    2013-10-01

    Full Text Available This work represents the results of the research ofessential oil contained in Sophora japonica L. flowerbuds volatile compounds collected during the nextstages of their development: green flower buds, formedflower buds and the beginning of flower buds opening.Essential oil assay content in Sophora japonica L.flower buds was determined with hydrodistillationmethod. Content of essential oil in the raw material isless than 0,1%. Qualitative composition and assaycontent of Sophora japonica L. flower buds essential oilconstituents were determined with chromato-massspectrometry method. In consequence of the research 80constituents were identified in Sophora japonica L.flower buds out of which 61 substances are during thegreen flower buds and beginning of flower budsopening stages, 66 substances are during formed flowerbuds stage. Substances are represented by aliphatic andcyclic terpenoids, their alcohols and ketones. Mostvolatile substances were extracted on the stage offormed buds.

  16. Room-temperature quantum noise limited spectrometry and methods of the same

    Science.gov (United States)

    Stevens, Charles G.; Tringe, Joseph W.; Cunningham, Christopher Thomas

    2014-08-26

    In one embodiment, a heterodyne detection system for detecting light includes a first input aperture adapted for receiving first light from a scene input, a second input aperture adapted for receiving second light from a local oscillator input, a broadband local oscillator adapted for providing the second light to the second input aperture, a dispersive element adapted for dispersing the first light and the second light, and a final condensing lens coupled to an infrared detector. The final condensing lens is adapted for concentrating incident light from a primary condensing lens onto the infrared detector, and the infrared detector is a square-law detector capable of sensing the frequency difference between the first light and the second light. More systems and methods for detecting light are described according to other embodiments.

  17. High resolution mass spectrometry method and system for analysis of whole proteins and other large molecules

    Science.gov (United States)

    Reilly, Peter T. A. [Knoxville, TN; Harris, William A [Naperville, IL

    2010-03-02

    A matrix assisted laser desorption/ionization (MALDI) method and related system for analyzing high molecular weight analytes includes the steps of providing at least one matrix-containing particle inside an ion trap, wherein at least one high molecular weight analyte molecule is provided within the matrix-containing particle, and MALDI on the high molecular weight particle while within the ion trap. A laser power used for ionization is sufficient to completely vaporize the particle and form at least one high molecular weight analyte ion, but is low enough to avoid fragmenting the high molecular weight analyte ion. The high molecular weight analyte ion is extracted out from the ion trap, and is then analyzed using a detector. The detector is preferably a pyrolyzing and ionizing detector.

  18. Improvement of the detector resolution in X-ray spectrometry by using the maximum entropy method

    International Nuclear Information System (INIS)

    Fernández, Jorge E.; Scot, Viviana; Giulio, Eugenio Di; Sabbatucci, Lorenzo

    2015-01-01

    In every X-ray spectroscopy measurement the influence of the detection system causes loss of information. Different mechanisms contribute to form the so-called detector response function (DRF): the detector efficiency, the escape of photons as a consequence of photoelectric or scattering interactions, the spectrum smearing due to the energy resolution, and, in solid states detectors (SSD), the charge collection artifacts. To recover the original spectrum, it is necessary to remove the detector influence by solving the so-called inverse problem. The maximum entropy unfolding technique solves this problem by imposing a set of constraints, taking advantage of the known a priori information and preserving the positive-defined character of the X-ray spectrum. This method has been included in the tool UMESTRAT (Unfolding Maximum Entropy STRATegy), which adopts a semi-automatic strategy to solve the unfolding problem based on a suitable combination of the codes MAXED and GRAVEL, developed at PTB. In the past UMESTRAT proved the capability to resolve characteristic peaks which were revealed as overlapped by a Si SSD, giving good qualitative results. In order to obtain quantitative results, UMESTRAT has been modified to include the additional constraint of the total number of photons of the spectrum, which can be easily determined by inverting the diagonal efficiency matrix. The features of the improved code are illustrated with some examples of unfolding from three commonly used SSD like Si, Ge, and CdTe. The quantitative unfolding can be considered as a software improvement of the detector resolution. - Highlights: • Radiation detection introduces distortions in X- and Gamma-ray spectrum measurements. • UMESTRAT is a graphical tool to unfold X- and Gamma-ray spectra. • UMESTRAT uses the maximum entropy method. • UMESTRAT’s new version produces unfolded spectra with quantitative meaning. • UMESTRAT is a software tool to improve the detector resolution.

  19. Improvements in fast-neutron spectroscopy methods (1961); Amelioration des methodes de spectrometrie des neutrons rapides (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Cambou, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-02-15

    This research aimed at improving fast-neutron electronic detectors based on n-p elastic scattering. The first part concerns proportional counters; careful constructional methods have made it possible to plot mono-energetic neutron spectra in the range 700 keV - 3 MeV with a resolution of 7 per cent. The second part concerns scintillation counters: an organic scintillator and an inorganic scintillator covered with a thin layer of a scattering agent. An exact study of the types of scintillation has made it possible to develop efficient discriminator circuits. Different neutron spectra plotted in the presence of a strong gamma background are presented. The last part deals with the development of form discrimination methods for the study, in the actual beam, of the elastic scattering of 14.58 MeV electrons. With hydrogen, the distribution f ({phi}) of the recoil protons is f({phi}) = 1 + 0.034 cos {phi} + 0.042 cos{sup 2} {phi}. With tritium the scattering is strongly anisotropic; the curve representing the variation of the differential cross-section for the elastic scattering in the centre of mass system is obtained with a target containing 1 cm{sup 3} of tritium. (author) [French] Le travail a porte sur l'amelioration des detecteurs electroniques de neutrons rapides bases sur la diffusion elastique n-p. La premiere partie est relative aux compteurs proportionnels; des methodes soignees de fabrication ont permis des traces de spectres de neutrons monoenergetiques dans le domaine 700 keV - 3 MeV avec une resolution de 7 pour cent. La deuxieme partie est relative au compteur a scintillations; scintillateur organique et scintillateur mineral recouvert d'un diffuseur mince. Une etude precise des formes de scintillations a permis la mise au point de circuits discriminateurs efficaces. Differents spectres de neutrons traces en presence d'un fond gamma intense sont presentes. La derniere partie est relative a la mise en oeuvre des methodes de discrimination de forme pour l

  20. Method for simultaneous analysis of eight analogues of vitamin D using liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Shah Iltaf

    2012-10-01

    Full Text Available Abstract Background Despite considerable global investigation over several decades, the roles of vitamin D in health and disease development remains convoluted. One recognised issue is the difficulty of accurately measuring the active forms of vitamin D. Advances made include some new methods addressing the potential interference by excluding epimers and isobars. However, there is no evidence that epimers are without function. Therefore, the aim of this study was to develop and validate, for the first time, a new assay to simultaneously measure levels of six forms of vitamin D along with two epimers. The assay was applied to multilevel certified reference material (CRM and 25 pooled human sera samples, obtained from the Vitamin D External Quality Assessment Scheme (DEQAS, to demonstrate its efficiency. Results The assay is capable of simultaneously measuring eight vitamin D analogues over the calibration ranges and LODs (in nmol/L of: 1α25(OH2D2 [0.015-1; 0.01], 1α25(OH2D3 [0.1-100; 0.01], 25OHD3 [0.5-100, 0.025], 3-epi-25OHD3 [0.1-100, 0.05], 25OHD2 [0.5-100, 0.025], 3-epi-25OHD2 [0.1-100, 0.05], vitamin D3 [0.5-100, 0.05] and vitamin D2 [0.5-100, 0.05], using stanozolol-d3 as internal standard. Certified reference material and external quality control samples (DEQAS were analysed to meet the standards outlined by National Institute of Standards and Technology (NIST. Validation steps included recovery and both precision and accuracy under inter- and intra-day variation limit of detection, and analysis of each analyte over a linear range. All validation parameters were in line with acceptable Food and Drug Administration (FDA guidelines. All eight analogues were quantified with the 25OHD levels being commensurate with DEQAS data. Conclusions This report details the application of a new LC-MS/MS based assay for the efficient analysis of eight analogues of vitamin D over a range of samples, which is a significant advance over the existing

  1. Apparatus and method for transient thermal infrared spectrometry of flowable enclosed materials

    Science.gov (United States)

    McClelland, John F.; Jones, Roger W.

    1993-03-02

    A method and apparatus for enabling analysis of a flowable material enclosed in a transport system having an infrared transparent wall portion. A temperature differential is transiently generated between a thin surface layer portion of the material and a lower or deeper portion of the material sufficient to alter the thermal infrared emission spectrum of the material from the black-body thermal infrared emission spectrum of the material, and the altered thermal infrared emission spectrum is detected through the infrared transparent portion of the transport system while the altered thermal infrared emission spectrum is sufficiently free of self-absorption by the material of emitted infrared radiation. The detection is effected prior to the temperature differential propagating into the lower or deeper portion of the material to an extent such that the altered thermal infrared emission spectrum is no longer sufficiently free of self-absorption by the material of emitted infrared radiation. By such detection, the detected altered thermal infrared emission spectrum is indicative of characteristics relating to molecular composition of the material.

  2. Spectrometry and emission tomographic image reconstruction stimulated by neutrons via EM algorithm and Monte Carlo Method

    International Nuclear Information System (INIS)

    Viana, Rodrigo Sartorelo Salemi

    2014-01-01

    The NSECT (Neutron Stimulated Emission Computed Tomography) figures as a new spectrographic technique able to evaluate in vivo the concentration of elements using the inelastic scattering reaction (n,n'). Since its introduction, several improvements have been proposed with the aim of investigating applications for clinical diagnosis and reduction of absorbed dose associated with CT acquisition. In this context, two new diagnostic applications are presented using spectroscopic and tomographic approaches from NSECT. A new methodology has also been proposed to optimize the sinogram sampling that is directly related to the quality of the reconstruction by the irradiation protocol. The studies were developed based on simulations with MCNP5 code. Diagnosis of Renal Cell Carcinoma (RCC) and the detection of breast microcalcifications were evaluated in studies conducted using a human phantom. The obtained results demonstrate the ability of the NSECT technique to detect changes in the composition of the modeled tissues as a function of the development of evaluated pathologies. The proposed method for optimizing sinograms was able to analytically simulate the composition of the irradiated medium allowing the assessment of quality of reconstruction and effective dose in terms of the sampling rate. However, future research must be conducted to quantify the sensitivity of detection according to the selected elements. (author)

  3. High Throughput Screening Method for Systematic Surveillance of Drugs of Abuse by Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry.

    Science.gov (United States)

    DiBattista, Alicia; Rampersaud, Dianne; Lee, Howard; Kim, Marcus; Britz-McKibbin, Philip

    2017-11-07

    New technologies are urgently required for reliable drug screening given a worldwide epidemic of prescription drug abuse and its devastating socioeconomic impacts on public health. Primary screening of drugs of abuse (DoA) currently relies on immunoassays that are prone to bias and are not applicable to detect an alarming array of psychoactive stimulants, tranquilizers, and synthetic opioids. These limitations impact patient safety when monitoring for medication compliance, drug substitution, or misuse/abuse and require follow-up confirmatory testing by more specific yet lower throughput instrumental methods. Herein, we introduce a high throughput platform for nontargeted screening of a broad spectrum of DoA and their metabolites based on multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). We demonstrate that MSI-CE-MS enables serial injections of 10 samples within a single run (high resolution MS with full-scan data acquisition. Unambiguous drug identification was achieved by four or more independent parameters, including comigration with a deuterated internal standard or in silico prediction of electromigration behavior together with accurate mass, most likely molecular formula, as well as MS/MS as required for confirmation testing. Acceptable precision was demonstrated for over 50 DoA at 3 concentration levels over 4 days (median coefficient of variance = 13%, n = 117) with minimal ion suppression, isobaric interferences, and sample carry-over (screening cutoff levels in human urine while allowing for systematic surveillance, specimen verification, and retrospective testing of designer drugs that elude conventional drug tests.

  4. Argon direct analysis in real time mass spectrometry in conjunction with makeup solvents: a method for analysis of labile compounds.

    Science.gov (United States)

    Yang, Hongmei; Wan, Debin; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

    2013-02-05

    Helium direct analysis in real time (He-DART) mass spectrometry (MS) analysis of labile compounds usually tends to be challenging because of the occurrence of prominent fragmentation, which obscures the assigning of an ion to an independent species or merely a fragment in a mixture. In the present work, argon DART (Ar-DART) MS in conjunction with makeup solvents has been demonstrated to analyze a variety of labile compounds including nucleosides, alkaloids, glucose, and other small molecules. The results presented here confirm that Ar-DART can generate significantly less energetic ions than conventional He-DART and is able to produce the intact molecular ions with little or no fragmentation in both positive and negative ion modes. Adding a makeup solvent (absolute ethyl alcohol, methanol, fluorobenzene, or acetone) to the argon gas stream at the exit of the DART ion source can result in 1-2 orders of magnitude increase in detection signals. The sensitivity attainable by Ar-DART was found to be comparable to that by He-DART. The investigation of influence of solvents improves our understanding of the fundamental desorption and ionization processes in DART. The practical application of this rapid and high throughput method is demonstrated by the successful analysis of a natural product (Crude Kusnezoff Monkshood) extract, demonstrating the great potential in mixture research.

  5. A rapid liquid chromatography tandem mass spectrometry-based method for measuring propranolol on dried blood spots.

    Science.gov (United States)

    Della Bona, Maria Luisa; Malvagia, Sabrina; Villanelli, Fabio; Giocaliere, Elisa; Ombrone, Daniela; Funghini, Silvia; Filippi, Luca; Cavallaro, Giacomo; Bagnoli, Paola; Guerrini, Renzo; la Marca, Giancarlo

    2013-05-05

    Propranolol, a non-selective beta blocker drug, is used in young infants and newborns for treating several heart diseases; its pharmacokinetics has been extensively evaluated in adult patients using extrapolation to treat pediatric population. The purpose of the present study was to develop and validate a method to measure propranolol levels in dried blood spots. The analysis was performed by using liquid chromatography/tandem mass spectrometry operating in multiple reaction monitoring mode. The calibration curve in matrix was linear in the concentration range of 2.5-200 μg/L with correlation coefficient r=0.9996. Intra-day and inter-day precisions and biases were less than 8.0% (n=10) and 11.5% (n=10) respectively. The recoveries ranged from 94 to 100% and the matrix effect did not result in a severe signal suppression. Propranolol on dried blood spot showed a good stability at three different temperatures for one month. This paper describes a micromethod for measuring propranolol levels on dried blood spot, which determines a great advantage in neonates or young infants during pharmacokinetic studies because of less invasive sampling and small blood volume required. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Nontargeted Screening Method for Illegal Additives Based on Ultrahigh-Performance Liquid Chromatography-High-Resolution Mass Spectrometry.

    Science.gov (United States)

    Fu, Yanqing; Zhou, Zhihui; Kong, Hongwei; Lu, Xin; Zhao, Xinjie; Chen, Yihui; Chen, Jia; Wu, Zeming; Xu, Zhiliang; Zhao, Chunxia; Xu, Guowang

    2016-09-06

    Identification of illegal additives in complex matrixes is important in the food safety field. In this study a nontargeted screening strategy was developed to find illegal additives based on ultrahigh-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS). First, an analytical method for possible illegal additives in complex matrixes was established including fast sample pretreatment, accurate UHPLC separation, and HRMS detection. Second, efficient data processing and differential analysis workflow were suggested and applied to find potential risk compounds. Third, structure elucidation of risk compounds was performed by (1) searching online databases [Metlin and the Human Metabolome Database (HMDB)] and an in-house database which was established at the above-defined conditions of UHPLC-HRMS analysis and contains information on retention time, mass spectra (MS), and tandem mass spectra (MS/MS) of 475 illegal additives, (2) analyzing fragment ions, and (3) referring to fragmentation rules. Fish was taken as an example to show the usefulness of the nontargeted screening strategy, and six additives were found in suspected fish samples. Quantitative analysis was further carried out to determine the contents of these compounds. The satisfactory application of this strategy in fish samples means that it can also be used in the screening of illegal additives in other kinds of food samples.

  7. Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications

    Directory of Open Access Journals (Sweden)

    V. Vijaya Bhaskar

    2015-04-01

    Full Text Available A rapid, sensitive and selective pseudoMRM (pMRM-based method for the determination of solutol HS15 (SHS15 in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC–MS/MS. The most abundant ions corresponding to SHS15 free polyethyleneglycol (PEG oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for pMRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector (ELSD. Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community, where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities (NCEs to address the spiky plasma concentration profiles. Keywords: SHS15, LC–MS/MS, Spiky profiles, Validation

  8. Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications.

    Science.gov (United States)

    Bhaskar, V Vijaya; Middha, Anil; Srivastava, Pratima; Rajagopal, Sriram

    2015-04-01

    A rapid, sensitive and selective pseudoMRM (pMRM)-based method for the determination of solutol HS15 (SHS15) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC-MS/MS). The most abundant ions corresponding to SHS15 free polyethyleneglycol (PEG) oligomers at m / z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for pMRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector (ELSD). Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community, where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities (NCEs) to address the spiky plasma concentration profiles.

  9. Validation of a Multiresidue Analysis Method for 379 Pesticides in Human Serum Using Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Shin, Yongho; Lee, Jonghwa; Lee, Jiho; Lee, Junghak; Kim, Eunhye; Liu, Kwang-Hyeon; Lee, Hye Suk; Kim, Jeong-Han

    2018-04-04

    A screening method for simultaneous analysis of 379 pesticides in human serum was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Electrospray ionization with positive/negative switching mode of LC-MS/MS was adopted, and scheduled multiple reaction monitoring for each target compound was established. The limit of quantitation was 10 ng/mL for 94.5% of the total pesticides, and the correlation coefficients of calibration were ≥0.990 for 93.9% of the pesticides. For the sample preparation, scaled-down QuEChERS were used. Serum (100 μL) was extracted with acetonitrile (400 μL), partitioned with magnesium sulfate (40 mg) and sodium chloride (10 mg), and the upper layer was used for analysis without further cleanup steps. For the accuracy and precision tests, most of the pesticides showed excellent results in intra- and interday conditions. In the recovery tests at 10, 50, and 250 ng/mL, 85.8-91.8% of all target compounds satisfied the recovery range of 70-120% (relative standard deviation ≤20%).

  10. Capillary Isoelectric Focusing-Mass Spectrometry Method for the Separation and Online Characterization of Intact Monoclonal Antibody Charge Variants.

    Science.gov (United States)

    Dai, Jun; Lamp, Jared; Xia, Qiangwei; Zhang, Yingru

    2018-02-06

    We report a new online capillary isoelectric focusing-mass spectrometry (CIEF-MS) method for monoclonal antibody (mAb) charge variant analysis using an electrokinetically pumped sheath-flow nanospray ion source and a time-of-flight MS with pressure-assisted chemical mobilization. To develop a successful, reliable CIEF-MS method for mAb, we have selected and optimized many critical, interrelating reagents and parameters that include (1) MS-friendly anolyte and catholyte; (2) a glycerol enhanced sample mixture that reduced non-CIEF electrophoretic mobility and band broadening; (3) ampholyte selected for balancing resolution and MS sensitivity; (4) sheath liquid composition optimized for efficient focusing, mobilization, and electrospray ionization; (5) judiciously selected CIEF running parameters including injection amount, field strength, and applied pressure. The fundamental premise of CIEF was well maintained as verified by the linear correlation (R 2 = 0.99) between pI values and migration time using a mixture of pI markers. In addition, the charge variant profiles of trastuzumab, bevacizumab, infliximab, and cetuximab, obtained using this CIEF-MS method, were corroborated by imaged CIEF-UV (iCIEF-UV) analyses. The relative standard deviations (RSD) of absolute migration time of pI markers were all less than 5% (n = 4). Triplicate analyses of bevacizumab showed RSD less than 1% for relative migration time to an internal standard and RSD of 7% for absolute MS peak area. Moreover, the antibody charge variants were characterized using the online intact MS data. To the best of our knowledge, this is the first time that direct online MS detection and characterization were achieved for mAb charge variants resolved by CIEF as indicated by a well-established linear pH gradient and correlated CIEF-UV charge variant profiles.

  11. A convenient method for calculation of ionic diffusion coefficients for accurate selected ion flow tube mass spectrometry, SIFT-MS

    Science.gov (United States)

    Dryahina, K.; Spanel, P.

    2005-07-01

    A method to calculate diffusion coefficients of ions important for the selected ion flow tube mass spectrometry, SIFT-MS, is presented. The ions, on which this method is demonstrated, include the SIFT-MS precursors H3O+(H2O)0,1,2,3, NO.+(H2O)0,1,2 and O2+ and the product ions relevant to analysis of breath trace metabolites ammonia (NH3+(H2O)0,1,2, NH4+(H2O)0,1,2), acetaldehyde (C2H4OH+(H2O)0,1,2), acetone (CH3CO+, (CH3)2CO+, (CH3)2COH+(H2O)0,1, (CH3)2CO.NO+), ethanol (C2H5OHH+(H2O)0,1,2) and isoprene (C5H7+, C5H8+, C5H9+). Theoretical model of the (12, 4) potential for interaction between the ions and the helium atoms is used, with the repulsive part approximated by the mean hard-sphere cross section and the attractive part describing ion-induced dipole interactions. The reduced zero-field mobilities at 300 K are calculated using the Viehland and Mason theory [L.A. Viehland, S.L. Lin, E.A. Mason, At. Data Nucl. Data Tables, 60 (1995) 37-95], parameterised by a simple formula as a function of the mean hard-sphere cross section, and converted to diffusion coefficients using the Einstein relation. The method is tested on a set of experimental data for simple ions and cluster ions.

  12. Method Comparison of Neutron Activation Analysis and Atomic Absorption Spectrometry for Determination of Zinc in Food Samples

    International Nuclear Information System (INIS)

    Endah Damastuti; Syukria Kurniawati; Natalia Adventini

    2009-01-01

    Zinc as a micro nutrient, has important roles in human metabolism system. It is required by the body in appropriate amount from food intake. Due to the very low concentration of Zinc in food, high selectivity and sensitivity analysis technique is required for the determination, such as Neutron Activation Analysis (NAA) and Atomic Absorption Spectrometry (AAS). In this experiment, both methods were compared in zinc analysis of food samples. The subject of this experiment is to examine of those methods conformity and improving the technique capability in zinc analysis in food sample. Those methods were validated by analyzing zinc in SRM NIST 1548a Typical Diet and were tested its accuracy and precision. The results of Zn concentration were 25.1 ± 2.14 mg/kg by NAA and 24.1 ± 1.40 mg/kg by AAS while the certificate value was 24.6 ± 1.80 mg/kg. Percentage of relative bias, %CV, μ-test score and HORRAT(Horwitz ratio) value given by NAA were 2%, 8.5%, 0.18 and 0.9 respectively, while %relative bias, %CV, μ-test score and HORRAT value given by AAS were 2%, 5.8 %, 0.20 and 0.6 respectively. The result obtained for Zn concentration in various food samples by NAA and AAS were varied from 13.7 – 29.3 mg/kg with mean value 19.8 mg/kg and 11.2 – 26.0 mg/kg with mean value 17.3 mg/kg (author)

  13. New method to determine the total carbonyl functional group content in extractable particulate organic matter by tandem mass spectrometry.

    Science.gov (United States)

    Dron, J; Zheng, W; Marchand, N; Wortham, H

    2008-08-01

    A functional group analysis method was developed to determine the quantitative content of carbonyl functional groups in atmospheric particulate organic matter (POM) using constant neutral loss scanning-tandem mass spectrometry (CNLS-MS/MS). The neutral loss method consists in monitoring the loss of a neutral fragment produced by the fragmentation of a precursor ion in a collision cell. The only ions detected are the daughter ions resulting from the loss of the neutral fragment under study. Then, scanning the loss of a neutral fragment characteristic of a functional group enables the selective detection of the compounds bearing the chemical function under study within a complex mixture. The selective detection of carbonyl functional groups was achieved after derivatization with pentafluorophenylhydrazine (PFPH) by monitoring the neutral loss of C(6)F(5)N (181 amu), which was characteristic of a large panel of derivatized carbonyl compounds. The method was tested on 25 reference mixtures of different composition, all containing 24 carbonyl compounds at randomly determined concentrations. The repeatability and calibration tests were satisfying as they resulted in a relative standard deviation below 5% and a linear range between 0.01 and 0.65 mM with a calculated detection limit of 0.0035 mM. Also, the relative deviation induced by changing the composition of the mixture while keeping the total concentration of carbonyl functional groups constant was less than 20%. These reliability experiments demonstrate the high robustness of the developed procedure for accurate carbonyl functional group measurement, which was applied to atmospheric POM samples. Copyright (c) 2008 John Wiley & Sons, Ltd.

  14. Determination of diazepam and its metabolites in serum by the use of liquid chromatography: Mass spectrometry method

    Directory of Open Access Journals (Sweden)

    Đorđević Snežana

    2007-01-01

    Full Text Available Background/Aim. Diazepam is a benzodiazepine anxyolitic. Metabolism of diazepam takes place in liver which generates pharmacologically active metabolites N-desmethyldiazepam, temazepam and oxazepam. The aim of this study was to develop and validate the method of liquid chromatographymass spectrometry (LC-MS for separation and determination of diazepam and its active metabolites in the serum of rats samples after i.p. application of diazepam in a dose of 10 mg/kg. Methods. The serum samples taken from Wistar rats, were used in LC-MS analysis after the application of 10 mg/kg of diazepam i.p. Results. After alkaline extraction from the serum samples with diethylether and separation on a C18 reversed-phase column by using mobile phase methanolglacial acetic acid-water (50:1:49 v/v, diazepam and its metabolites were quantified. Determination was performed in a selective ion monitoring (SIM mode, thereby the other exogenous and endogenous compounds did not interfere with this assay. Diazepam, N-desmethyldiazepam, oxazepam and temazepam were eluted in 14 minutes. The standard curve was linear in the range from 10-2 000 ng/ml. The limits of detection for diazepam, N-desmethyldiazepam, oxazepam and temazepam were 4.37, 3.13, 4.38 and 7.31 ng/ml, respectively. The limits of quantitation for diazepam, Ndesmethyldiazepam, oxazepam and temazepam were 14.58, 10.41, 14.59 and 24.36 ng/ml, respectively. Conclusion. The described LC-MS is a simple, sensitive, specific and accurate method and could be used for routine identification and quantification of small concentrations of diazepam and its metabolites in biological fluids.

  15. Rapid methods to determine procyanidins, anthocyanins, theobromine and caffeine in rat tissues by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Serra, Aida; Macià, Alba; Romero, Maria-Paz; Piñol, Carme; Motilva, Maria-José

    2011-06-01

    Rapid, selective and sensitive methods were developed and validated to determine procyanidins, anthocyanins and alkaloids in different biological tissues, such as liver, brain, the aorta vein and adipose tissue. For this purpose, standards of procyanidins (catechin, epicatechin, and dimer B(2)), anthocyanins (cyanidin-3-glucoside and malvidin-3-glucoside) and alkaloids (theobromine, caffeine and theophylline) were used. The methods included the extraction of homogenized tissues by off-line liquid-solid extraction, and then solid-phase extraction to analyze alkaloids, or microelution solid-phase extraction plate for the analysis of procyanidins and anthocyanins. The eluted extracts were then analyzed by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, using a triple quadrupole as the analyzer. The optimum extraction solution was water/methanol/phosphoric acid 4% (94/4.5/1.5, v/v/v). The extraction recoveries were higher than 81% for all the studied compounds in all the tissues, except the anthocyanins, which were between 50 and 65% in the liver and brain. In order to show the applicability of the developed methods, different rat tissues were analyzed to determine the procyanidins, anthocyanins and alkaloids and their generated metabolites. The rats had previously consumed 1g of a grape pomace extract (to analyze procyanidins and anthocyanins) or a cocoa extract (to analyze alkaloids) per kilogram of body weight. Different tissues were extracted 4h after administration of the respective extracts. The analysis of the metabolites revealed a hepatic metabolism of procyanidins. The liver was the tissue which produced a greater accumulation of these metabolites. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Quantitative determination of hederagenin in rat plasma and cerebrospinal fluid by ultra fast liquid chromatography-tandem mass spectrometry method.

    Science.gov (United States)

    Yang, Xuemei; Li, Guoliang; Chen, Lingyun; Zhang, Cong; Wan, Xinxiang; Xu, Jiangping

    2011-07-01

    A rapid, sensitive and selective method was developed for the quantitative determination of hederagenin in rat plasma and cerebrospinal fluid (CSF) by ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS). It has been successfully applied in a pharmacokinetic study of hederagenin in the central nervous system (CNS). Sample pretreatment involved a simple protein precipitation with methanol and a one-step extraction with ethyl acetate. Separation was carried out in a Shim-pack XR-ODS II (75 mm × 2.0 mm, i.d., 2.1 μm) column with gradient elution at a flow rate of 0.35 mL/min. The mobile phase was 5mM ammonium acetate and acetonitrile. Detection was performed in a triple-quadruple tandem mass spectrometer by multiple-reaction-monitoring mode via electrospray ionization. A linear calibration curve for hederagenin was obtained over a concentration range of 0.406 (lower limit of quantification, LLOQ) to 203 ng/mL (r² > 0.99) for both plasma and CSF. The intra-day and inter-day precision (relative standard deviation, RSD) values were less than 15%. At all quality control (QC) levels, the accuracy (relative error, RE) was within -9.0% and 11.1% for plasma and CSF, respectively. The pharmacokinetics results indicated that hederagenin could pass through the blood-brain barrier. This UFLC-MS/MS method demonstrates higher sensitivity and sample throughput than previous methods. It was also successfully applied to the pharmacokinetic study of hederagenin following oral administration of Fructus akebiae extract in rats. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. An analytical method for cyclosporine using liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Kanduru, Srividya V; Somayaji, Vishwa; Lavasanifar, Afsaneh; Brocks, Dion R

    2010-02-01

    A liquid chromatographic mass spectrometric (LC-MS) assay has been developed for cyclosporine A (CyA) in rat plasma using amiodarone as internal standard (IS). Rat plasma (100 microL) containing drug and IS were extracted using liquid-liquid extraction with 4 mL of 95:5 ether:methanol. After evaporation of the organic layer the residue was reconstituted with 500 microL of water. Then the aqueous layer was transferred to LC-MS sample vials. A 10 microL volume was injected. The analysis was performed on a C(8) column 3.5 microm (2.1 x 50 mm) heated to 60 degrees C with a mobile phase consisting of acetonitrile:methanol:0.2% NH(4)OH (60:20:20) at an isocratic flow-rate of 0.2 mL/min. The ions used for quantitation of CyA and IS were m/z 1202.8 and 645.9, with retention times of 3.35 and 4.72 min, respectively. Linear relationships (r(2) > 0.99) were achieved between plasma or blood concentration and peak height ratios (drug:IS) over the concentration range 50-5000 ng/mL. The CV% and mean error were <19%. Based on validation data, the lower limit of quantification for the assay was 50 ng/mL. The reported assay method displayed high measures of linearity, sensitivity, reliability and precision, allowing its applicability in pharmacokinetic studies in rat. (c) 2009 John Wiley & Sons, Ltd.

  18. A novel tandem mass spectrometry method for first-line screening of mainly beta-thalassemia from dried blood spots.

    Science.gov (United States)

    Yu, Chaowen; Huang, Shuodan; Wang, Ming; Zhang, Juan; Liu, Hao; Yuan, Zhaojian; Wang, Xingbin; He, Xiaoyan; Wang, Jie; Zou, Lin

    2017-02-10

    Traditional methods for thalassemia screening are time-consuming and easily affected by cell hemolysis or hemoglobin degradation in stored blood samples. Tandem mass spectrometry (MS/MS) proved to be an effective technology for sickle cell disorders (SCD) screening. Here, we developed a novel MS/MS method for β-thalassemia screening from dried blood spots (DBS). Stable isotopic-labeled peptides were used as internal standards for quantification and calculation of the α:β-globin ratios. We used the α:β-globin ratio cutoffs to differentiate between normal individuals and patients with thalassemia. About 781 patients and 300 normal individuals were analyzed. The α:β-globin ratios showed significant difference between normal and β-thalassemia patients (Pthalassemia mutation. In the parallel study, all cases screened for suspected thalassemia from six hundred DBS samples by using this MS/MS method were successfully confirmed by genotyping. The intra-assay and inter-assay CVs of the ratios ranged from 2.4% to 3.9% and 4.7% to 7.1%, and there was no significant sample carryover or matrix effect for this MS/MS method. Combined with SCD screening, this MS/MS method could be used as a first-line screening assay for both structural and expression abnormalities of human hemoglobin. Traditional methods for thalassemia screening were depending on the structural integrity of tetramers and could be affected by hemolysis and degradation of whole blood samples, especially when stored. We used proteospecific peptides produced by the tryptic digestion of each globin to evaluate the production ratio between α- and β-globin chains, which turned out to be quite stable even when stored for more than two months. Though most of the peptides were specific to α-globin or β-globin, we only chose four most informative peptides and its stable isotopic-labeled peptides as internal standards for analysis, which could obtain a high accuracy. Currently, we are the first to address the

  19. Setting up of a liquid chromatography-high resolution tandem mass spectrometry method for the detection of caseins in food. A comparison with ELISA method

    Directory of Open Access Journals (Sweden)

    Daniela Gastaldi

    2013-06-01

    Full Text Available Determination of caseins in food matrices is usually performed by using the competitiveenzyme- linked immunosorbent assay (ELISA technique. However such a technique suffers from a number of limitations. Among these, the applicability to a narrow concentration range, a non linear (logarithmic response, a non-negligible cross-reactivity and a high cost per kit. At the time of the completion of this study, in case of ELISA positive feedback, there was poor availability in the literature of finding reliable instrumental methods able to determine both qualitatively and quantitatively this class of substances. In the present study, a liquid chromatography-high resolution tandem mass spectrometry (HPLC-HRMS/MS instrumental method was developed with a high resolution mass spectrometer (Orbitrap. Real samples of sausages in which caseins were detected by ELISA technique were analysed. A casein-free sample of ham was used as a blank. The analytical characteristics of the instrumental method were compared with those of a commercial ELISA test, declared specific for α- and β-casein.

  20. Signal-to-noise ratio of FT-IR CO gas spectra

    DEFF Research Database (Denmark)

    Bak, J.; Clausen, Sønnik

    1999-01-01

    in emission and transmission spectrometry, an investigation of the SNR in CO gas spectra as a function of spectral resolution has been carried out. We present a method to (1) determine experimentally the SNR at constant throughput, (2) determine the SNR on the basis of measured noise levels and Hitran......The minimum amount of a gaseous compound which can be detected and quantified with Fourier transform infrared (FT-IR) spectrometers depends on the signal-to-noise ratio (SNR) of the measured gas spectra. In order to use low-resolution FT-IR spectrometers to measure combustion gases like CO and CO2...... simulated signals, and (3) determine the SNR of CO from high to low spectral resolutions related to the molecular linewidth and vibrational-rotational lines spacing. In addition, SNR values representing different spectral resolutions but scaled to equal measurement times were compared. It was found...

  1. Aroma composition of red wines by different extraction methods and Gas Chromatography-SIM/MASS spectrometry analysis.

    Science.gov (United States)

    Genovese, Alessandro; Dimaggio, Rosa; Lisanti, Maria Tiziana; Piombino, Paola; Moio, Luigi

    2005-06-01

    One hundred and one volatile compounds, reported in literature as powerful odorants of wine, were quantified by Gas Chromatography-Selective Ion Monitoring/Mass Spectrometry (GC-SIM/MS) in Primitivo, Aglianico, Merlot and Cabernet Sauvignon red wines. Wine samples were extracted by 3 different extraction methods: 1) separation of the alcoholic fraction from the aqueous phase by salting-out and subsequent extraction by liquid-liquid micro-extraction with 1,1,2-trichlorotrifluoroethane (Freon 113); 2) extraction by liquid-liquid micro-extraction with dichloromethane; 3) solid phase extraction (SPE cartridge: 800 mg of LiChrolut EN resin) with pentane-dichloromethane (20:1) and dichloromethane. The selection of the ion fragments used for quantification was directly performed on a red wine sample. For each compound the area of the corresponding peak was normalized respect to the peak of the internal standard and then interpolated in a calibration curve obtained analysing a model wine solution (water, ethanol, tartaric acid and known amounts of analytes and of internal standard). The methods showed a good linearity: r2>0.990, except for farnesol (isomer a and c), octanal, decanal, furaneol and phenylacetic acid with 0.966 furaneol and sotolon. The Aglianico wines were characterised by the major fermentation compounds (esters, fatty acids and 2-phenylethanol), beta-damascenone, beta-ionone and linalool. The Primitivo wines were characterized by furaneol, methoxypyrazine, gamma-nonalactone and acetaldehyde, while Cabernet Sauvignon and Merlot wines principally by cask derivates (vanillin, (Z) 3-methyl-gamma-octalactone [(Z) wiskylactone], maltol and eugenol), some aldehydes and 3-isopropyl-2-methoxypyrazine.

  2. New ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of irbesartan in human plasma

    Directory of Open Access Journals (Sweden)

    Tanveer A. Wani

    2015-09-01

    Full Text Available With the objective of reducing analysis time and maintaining good efficiency, there has been substantial focus on high-speed chromatographic separations and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS is a preeminent analytical tool for rapid biomedical analysis. In this study a simple, rapid, sensitive, and specific ultra-performance liquid chromatography-MS/MS method was developed and validated for quantification of the angiotensin II receptor antagonist, irbesartan (IRB, in human plasma. After a simple protein precipitation using methanol and acetonitrile, IRB and internal standard (IS telmisartan were separated on Acquity UPLC BEH C18 column (50 mm × 2.1 mm, i.d. 1.7 μm, Waters, Milford, MA, USA using a mobile phase consisted of acetonitrile: methanol: 10 mM ammonium acetate (70: 15: 15 v/v/v with a flow rate of 0.4 mL/min and detected MS/MS in negative ion mode. The ion transitions recorded in multiple reaction monitoring mode were m/z 427.2→193.08 for IRB and m/z 513.2→469.3 for IS. The assay exhibited a linear dynamic range of 2–500 ng/mL for IRB in human plasma with good correlation coefficient of (0.995 and with a lower limit of quantitation of 2 ng/mL. The intra- and interassay precisions were satisfactory; the relative standard deviations did not exceed 9.91%. The proposed UPLC-MS/MS method is simple, rapid, and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.

  3. Fast and simple method for determination of fatty acid methyl esters (FAME) in biodiesel blends using X-ray spectrometry.

    Science.gov (United States)

    Sitko, Rafal; Zawisza, Beata; Kowalewska, Zofia; Kocot, Karina; Polowniak, Marzena

    2011-09-30

    The determination of fatty acid methyl esters (FAME) in diesel fuel blends is an important aspect of production and blending process as well as quality control of distribution operations. In this study, energy-dispersive X-ray fluorescence spectrometer (EDXRF) is used for the first time for determination of FAME in biodiesel blends. The principle of the method is based on intensity difference of X-ray radiation scattered from hydrocarbons and from FAME. The experiment shows that coherent and incoherent radiation, commonly applied for evaluation of the average atomic number of the sample with light matrix, cannot be applied for FAME determination. However, the application of scattered continuous radiation gives excellent correlation between FAME concentration and intensity of scattered radiation. The best results are obtained if continuum is collected in the range of energy between 10.5 and 15.0 keV for rhodium X-ray tube, operated at 35 kV. Linear relationship between the FAME concentration and the inverse of scattered continuous radiation is obtained with the correlation coefficients of 0.999. Standard deviation of measurement is ca. 0.46% (v/v) of FAME and detection limit is 1.2% (v/v) for 600 s counting time and 50% dead-time loss using Si-PIN detector. The investigation shows that crucial issue in determination of FAME in biodiesel blends using EDXRF spectrometer is the precision of measurements resulting from the counting statistics. Therefore, much better results (0.20% (v/v) standard deviation and 0.52% (v/v) detection limit) can be expected if higher intensity of primary radiation is applied and X-ray spectrum is collected by silicon drift detector of high input count rate. For concentration of FAME from 10 to 100% (v/v), the differences between reference method (Fourier transform infrared spectrometry) and the proposed method usually do not exceed 1% (v/v) of FAME. The proposed method is fast, simple and enables FAME determination in wide range of

  4. Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action.

    Science.gov (United States)

    Rabiee, Atefeh; Krüger, Marcus; Ardenkjær-Larsen, Jacob; Kahn, C Ronald; Emanuelli, Brice

    2018-07-01

    Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type, IRS-1 -/- and IRS-2 -/- mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1. These regulated sites included previously reported substrates of the insulin/IGF-1 signalling pathway, as well as novel substrates including Nuclear Factor I X and Semaphorin-4B. In silico prediction suggests the protein kinase B (PKB), protein kinase C (PKC), and cyclin-dependent kinase (CDK) as the main mediators of these phosphorylation events. Importantly, we found preferential phosphorylation patterns depending on the presence of either IRS-1 or IRS-2, which was associated with specific sets of kinases involved in signal transduction downstream of these substrates such as PDHK1, MAPK3, and PKD1 for IRS-1, and PIN1 and PKC beta for IRS-2. Overall, by generating a comprehensive phosphoproteomic profile from brown preadipocyte cells in response to IGF-1 stimulation, we reveal both common and distinct insulin/IGF-1 signalling events mediated by specific IRS proteins. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Desarrollo de un método de CLAR-IR para la determinación de etanol residual en vacuna Development of a HPLC-IR method for determination of residual ethanol in vaccine

    Directory of Open Access Journals (Sweden)

    Matilde Cuevas Valdespino

    2009-08-01

    , the aim of present papers was to develop an ethanol assessment method by liquid high performance-refraction index chromatography to these aims and its comparison with a frequent used method to quantify this solvent, like in the case of gas chromatography. Method assessed was very useful and with a good robustness for determination of this organic solvent in this anti-meningococcal vaccine. There were not statistically significant differences among results obtained with assessment of the same samples of vaccine by both chromatographic methods (high resolution liquid and gas, indicating possibility of high performance liquid chromatography use in substitution of the gas one for this determination.

  6. Annotation of the human serum metabolome by coupling three liquid chromatography methods to high-resolution mass spectrometry.

    Science.gov (United States)

    Boudah, Samia; Olivier, Marie-Françoise; Aros-Calt, Sandrine; Oliveira, Lydie; Fenaille, François; Tabet, Jean-Claude; Junot, Christophe

    2014-09-01

    This work aims at evaluating the relevance and versatility of liquid chromatography coupled to high resolution mass spectrometry (LC/HRMS) for performing a qualitative and comprehensive study of the human serum metabolome. To this end, three different chromatographic systems based on a reversed phase (RP), hydrophilic interaction chromatography (HILIC) and a pentafluorophenylpropyl (PFPP) stationary phase were used, with detection in both positive and negative electrospray modes. LC/HRMS platforms were first assessed for their ability to detect, retain and separate 657 metabolite standards representative of the chemical families occurring in biological fluids. More than 75% were efficiently retained in either one LC-condition and less than 5% were exclusively retained by the RP column. These three LC/HRMS systems were then evaluated for their coverage of serum metabolome. The combination of RP, HILIC and PFPP based LC/HRMS methods resulted in the annotation of about 1328 features in the negative ionization mode, and 1358 in the positive ionization mode on the basis of their accurate mass and precise retention time in at least one chromatographic condition. Less than 12% of these annotations were shared by the three LC systems, which highlights their complementarity. HILIC column ensured the greatest metabolome coverage in the negative ionization mode, whereas PFPP column was the most effective in the positive ionization mode. Altogether, 192 annotations were confirmed using our spectral database and 74 others by performing MS/MS experiments. This resulted in the formal or putative identification of 266 metabolites, among which 59 are reported for the first time in human serum. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Validation of the Mass-Extraction-Window for Quantitative Methods Using Liquid Chromatography High Resolution Mass Spectrometry.

    Science.gov (United States)

    Glauser, Gaétan; Grund, Baptiste; Gassner, Anne-Laure; Menin, Laure; Henry, Hugues; Bromirski, Maciej; Schütz, Frédéric; McMullen, Justin; Rochat, Bertrand

    2016-03-15

    A paradigm shift is underway in the field of quantitative liquid chromatography-mass spectrometry (LC-MS) analysis thanks to the arrival of recent high-resolution mass spectrometers (HRMS). The capability of HRMS to perform sensitive and reliable quantifications of a large variety of analytes in HR-full scan mode is showing that it is now realistic to perform quantitative and qualitative analysis with the same instrument. Moreover, HR-full scan acquisition offers a global view of sample extracts and allows retrospective investigations as virtually all ionized compounds are detected with a high sensitivity. In time, the versatility of HRMS together with the increasing need for relative quantification of hundreds of endogenous metabolites should promote a shift from triple-quadrupole MS to HRMS. However, a current "pitfall" in quantitative LC-HRMS analysis is the lack of HRMS-specific guidance for validated quantitative analyses. Indeed, false positive and false negative HRMS detections are rare, albeit possible, if inadequate parameters are used. Here, we investigated two key parameters for the validation of LC-HRMS quantitative analyses: the mass accuracy (MA) and the mass-extraction-window (MEW) that is used to construct the extracted-ion-chromatograms. We propose MA-parameters, graphs, and equations to calculate rational MEW width for the validation of quantitative LC-HRMS methods. MA measurements were performed on four different LC-HRMS platforms. Experimentally determined MEW values ranged between 5.6 and 16.5 ppm and depended on the HRMS platform, its working environment, the calibration procedure, and the analyte considered. The proposed procedure provides a fit-for-purpose MEW determination and prevents false detections.

  8. Land drainage system detection using IR and visual imagery taken from autonomous mapping airship and evaluation of physical and spatial parameters of suggested method

    Science.gov (United States)

    Koska, Bronislav; Křemen, Tomáš; Štroner, Martin; Pospíšil, Jiří; Jirka, Vladimír.

    2014-10-01

    An experimental approach to the land drainage system detection and its physical and spatial parameters evaluation by the form of pilot project is presented in this paper. The novelty of the approach is partly based on using of unique unmanned aerial vehicle - airship with some specific properties. The most important parameters are carrying capacity (15 kg) and long flight time (3 hours). A special instrumentation was installed for physical characteristic testing in the locality too. The most important is 30 meter high mast with 3 meter length bracket at the top with sensors recording absolute and comparative temperature, humidity and wind speed and direction in several heights of the mast. There were also installed several measuring units recording local condition in the area. Recorded data were compared with IR images taken from airship platform. The locality is situated around village Domanín in the Czech Republic and has size about 1.8 x 1.5 km. There was build a land drainage system during the 70-ties of the last century which is made from burnt ceramic blocks placed about 70 cm below surface. The project documentation of the land drainage system exists but real state surveying haveńt been never realized. The aim of the project was land surveying of land drainage system based on infrared, visual and its combination high resolution orthophotos (10 cm for VIS and 30 cm for IR) and spatial and physical parameters evaluation of the presented procedure. The orthophoto in VIS and IR spectrum and its combination seems to be suitable for the task.

  9. A conformational study of protonated noradrenaline by UV-UV and IR dip double resonance laser spectroscopy combined with an electrospray and a cold ion trap method.

    Science.gov (United States)

    Wako, Hiromichi; Ishiuchi, Shun-Ichi; Kato, Daichi; Féraud, Géraldine; Dedonder-Lardeux, Claude; Jouvet, Christophe; Fujii, Masaaki

    2017-05-03

    The conformer-selected ultraviolet (UV) and infrared (IR) spectra of protonated noradrenaline were measured using an electrospray/cryogenic ion trap technique combined with photo-dissociation spectroscopy. By comparing the UV photo dissociation (UVPD) spectra with the UV-UV hole burning (HB) spectra, it was found that five conformers coexist under ultra-cold conditions. Based on the spectral features of the IR dip spectra of each conformer, two different conformations on the amine side chain were identified. Three conformers (group I) were assigned to folded and others (group II) to extended structures by comparing the observed IR spectra with the calculated ones. Observation of the significantly less-stable extended conformers strongly suggests that the extended structures are dominant in solution and are detected in the gas phase by kinetic trapping. The conformers in each group are assignable to rotamers of OH orientations in the catechol ring. By comparing the UV-UV HB spectra and the calculated Franck-Condon spectra obtained by harmonic vibrational analysis of the S 1 state, with the aid of relative stabilization energies of each conformer in the S 0 state, the absolute orientations of catechol OHs of the observed five conformers were successfully determined. It was found that the 0-0 transition of one folded conformer is red-shifted by about 1000 cm -1 from the others. The significant red-shift was explained by a large contribution of the πσ* state to S 1 in the conformer in which an oxygen atom of the meta-OH group is close to the ammonium group.

  10. Solid-phase microextraction/gas chromatography-mass spectrometry method optimization for characterization of surface adsorption forces of nanoparticles.

    Science.gov (United States)

    Omanovic-Miklicanin, Enisa; Valzacchi, Sandro; Simoneau, Catherine; Gilliland, Douglas; Rossi, Francois

    2014-10-01

    A complete characterization of the different physico-chemical properties of nanoparticles (NPs) is necessary for the evaluation of their impact on health and environment. Among these properties, the surface characterization of the nanomaterial is the least developed and in many cases limited to the measurement of surface composition and zetapotential. The biological surface adsorption index approach (BSAI) for characterization of surface adsorption properties of NPs has recently been introduced (Xia et al. Nat Nanotechnol 5:671-675, 2010; Xia et al. ACS Nano 5(11):9074-9081, 2011). The BSAI approach offers in principle the possibility to characterize the different interaction forces exerted between a NP's surface and an organic--and by extension biological--entity. The present work further develops the BSAI approach and optimizes a solid-phase microextraction gas chromatography-mass spectrometry (SPME/GC-MS) method which, as an outcome, gives a better-defined quantification of the adsorption properties on NPs. We investigated the various aspects of the SPME/GC-MS method, including kinetics of adsorption of probe compounds on SPME fiber, kinetic of adsorption of probe compounds on NP's surface, and optimization of NP's concentration. The optimized conditions were then tested on 33 probe compounds and on Au NPs (15 nm) and SiO2 NPs (50 nm). The procedure allowed the identification of three compounds adsorbed by silica NPs and nine compounds by Au NPs, with equilibrium times which varied between 30 min and 12 h. Adsorption coefficients of 4.66 ± 0.23 and 4.44 ± 0.26 were calculated for 1-methylnaphtalene and biphenyl, compared to literature values of 4.89 and 5.18, respectively. The results demonstrated that the detailed optimization of the SPME/GC-MS method under various conditions is a critical factor and a prerequisite to the application of the BSAI approach as a tool to characterize surface adsorption properties of NPs and therefore to draw any further

  11. A new method for calibrating the current gain of 1013 Ω amplifiers in thermal ionization mass spectrometry.

    Science.gov (United States)

    Wang, Guiqin; Zeng, Yuling; Xu, Jifeng; Liu, Wengui

    2018-03-09

    We report a new method for calibrating the current gain of 10 13 Ω amplifiers in both positive and negative mode used in thermal ionisation mass spectrometry (TIMS). This method uses any isotopic standard or sample to calibrate the gain factor as long as it can produce a stable current signal. It is simpler and more flexible than that recommended by Thermo-Fisher (the manufacture of the TIMS). In these analyses, the gains of five 10 13 Ω amplifiers were assessed. The precision of gain factors was better than 100 ppm (2 RSD) in a day, and the long term reproducibility was better than 300 ppm (2 RSD) within 2 - 8 months. After a gain was calibrated, the ratio accuracy and precision in the positive mode for 87 Sr/ 88 Sr of NIST 987 Sr and 143 Nd/ 144 Nd of La Jolla Nd were 0.710242 ± 60 (2 SD, n = 14) and 0.511842 ± 10 (2 SD, n = 22), respectively, at intensities of 88 Sr 0.3 V and 142 Nd 0.4 V, while in the negative mode for 187 Os/ 188 Os of Merck Os was 0.120229± 34 (2 SD, n = 23) at an intensity of 187 OsO 3 0.01 mV. In addition, a difference in the gain factors between the negative mode TIMS (NTIMS) and positive mode TIMS (PTIMS) has been recognized. The values of the gain factor for NTIMS and PTIMS show a deviation of 0.54% on the Triton and 0.31% on the Triton Plus TIMS in this study; therefore, gain calibration should be carried out on both NTIMS and PTIMS. Moreover, a bias of ~ 1.5×10 -5 between H and L Faraday cups for the same 10 13 Ω amplifier has been detected, hinting that the efficiency of different Faraday cups may affect the gain factors, which can be eliminated through the new method of "cross-calibration" discribed in this study. This article is protected by copyright. All rights reserved.

  12. Reliability of graphite furnace atomic absorption spectrometry as ...

    African Journals Online (AJOL)

    spectrometry as alternative method for trace analysis of ... Purpose: To evaluate the comparative efficiency of graphite furnace atomic absorption spectrometry .... Methods comparison and validation .... plasma-optical emission spectrometry.

  13. Developments in gamma-ray spectrometry: systems, software, and methods-II. 3. Low-Energy Gamma-Ray Spectrometry Using a Compton-Suppressed Telescope Detector

    International Nuclear Information System (INIS)

    Sigg, R.A.; DiPrete, D.P.

    2001-01-01

    The Savannah River Technology Center (SRTC) utilizes gamma-ray spectrometry in studying numerous areas of applied interest to the Savannah River Site (SRS). For example, analyses of long-lived gamma-ray-emitting fission products and actinides are required to meet waste characterization, process holdup, environmental restoration, and decontamination and decommissioning efforts. A significant portion of the overall effort centers on measurements of gamma rays having energies below several hundred kilo-electron-volts. To assist these efforts, the SRTC recently acquired a spectrometer system that provides lower natural and Compton scattered background levels while achieving relatively high counting efficiencies for low-energy gamma rays. The combination of high efficiency and low background provides factor-of- 2-to-4 improvements in minimum detectable activities and allows meeting programmatic objectives with shorter measurement times. Numerous Compton-suppression spectrometers have been reported since the concept was first advanced. The spectrometer consists of two high-purity germanium detectors in a telescope configuration surrounded by a background /Compton-suppression sodium iodide detector. The front germanium detector is a 20-mm-thick x 60-mm-diam broad energy spectrometer, and the rear detector is a 40% efficient 61- mm-diam x 60-cm-thick closed-end coaxial spectrometer. The cryostat housing the germanium detectors (a) includes a carbon composite window for transmitting low-energy gamma rays, (b) is in a J-type configuration to mask the germanium detectors from natural activities in the cryo-pumping media, and (c) is fabricated from materials selected for low background. The telescope detector is in the 8.6-cm-inside-diameter annulus of a 22.9- x 22.9-cm sodium iodide detector encased in a 10-cm-thick lead shield. The counting system is located in a basement counting room having ∼60-cm-thick concrete walls. Initial tests show that the low-energy segment of

  14. Trace mercury determination in drinking and natural water after preconcentration and separation by DLLME-SFO method coupled with cold vapor atomic absorption spectrometry

    OpenAIRE

    Abdollahi Atousa; Amirkavehei Mooud; Gheisari Mohammad Mehdi; Tadayon Fariba

    2014-01-01

    A novel dispersive liquid–liquid microextraction based on solidification of floating organic drop (DLLME-SFO) for simultaneous separation/preconcentration of ultra trace amounts of mercury was used. A method based on amalgamation was used for collection of gaseous mercury on gold coated sand (Gold trap). The concentration of mercury was determined by cold vapor atomic absorption spectrometry (CV-AAS). The DLLME-SFO behavior of mercury by using dithizone as complexing agent was systematically ...

  15. Integration of nuclear spectrometry methods as a new approach to material research. Final report of a coordinated research project 2006-2009

    International Nuclear Information System (INIS)

    2011-10-01

    In 2006, the IAEA initiated a coordinated research project (CRP) on 'Unification of Nuclear Spectrometries: Integrated Techniques as a New Tool for Material Research' as one of the elements of a project on 'Improvements in Nuclear Spectrometry Applications'. The major objective was to assist laboratories in Member States in enhancing proper utilization of nuclear analytical methods and to help them develop nuclear instruments for special applications. An overall objective of the CRP was to help Member States to improve characterization of materials by the effective utilization of nuclear spectrometry instruments and techniques as well as by developing integrated/unified instruments and analytical methodologies in support of environmental pollution monitoring, industry, study of cultural heritage, human health, agriculture, etc. These techniques can be used in small laboratories as well as in state of the art synchrotron sources. The specific research objectives of the CRP included development (or upgrading) of integrated multifunctional instruments based on nuclear spectrometries and related techniques as well as development of software for the handling and operation of integrated multifunctional instruments, including data acquisition. The CRP also covered: development (or upgrading) of integrated analytical approaches/methodologies and software for processing and presentation of data collected by multifunctional instruments; extension of the applications of integrated/unified instruments; and synergistic and complementary use of nuclear spectrometries, with the aim of assisting end users of nuclear spectrometries in various fields. The CRP covered a period of four years (2006-2009). Twelve laboratories from both developed and developing Member States and the IAEA's Laboratories participated. The first research coordination meeting (RCM) was held in Vienna, from 16 to 20 April 2007. The participants presented progress reports, reviewed the status of the

  16. A simple solid-phase extraction method for the analysis of red cell phospholipids by liquid chromatography- tandem mass spectrometry.

    Science.gov (United States)

    Nguyen, Van Long

    2018-02-25

    There has been increasing interest in the analysis of phospholipids in red blood cells as potential long-term biomarkers of different disease states. Here, we describe a simple method for the analysis of two phospholipids: 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanol (PE 16:0/18:1) and 1-Palmitoyl-2-linoleoyl-sn-glycero-3-phosphoethanol (PE 16:/0/18:2) in erythrocytes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Whole blood samples were removed free of plasma and washed in isotonic saline. Red cells were lysed with ultrapure water. Lysate samples were processed using a hybrid solid-phase extraction (SPE) phospholipid cartridge (1 mL, 30 mg). Both PE 16:0/18:1 and PE 16:0/18:2 and their deuterated internal standards were separated on an ACE C4 (150 mm × 2.1 mm, 2.7 μm particle size) by gradient elution at a flow rate of 0.5 mL per minute using mobile phases consisting of 0.01 mol/L ammonium acetate in: water (A), methanol (B), and isopropanol (C). The phospholipid species were quantified by the following transitions: PE 16:0/18:1: 701.5→281.3 and PE 16:0/18:2: 699.5→279.3. Both PE species displayed linearity ranging from 10 to 500 μg/L. The coefficient of variation (CV%) of PE 16:0/18:1 concerning intraday and interday precision was between 1.9%-2.6% and 3.0%-4.3%, respectively. For PE 16:0/18:2, this was between 1.8%-3.4% and 3.7%-4.1%, respectively. Both phospholipid species had accuracy (PE 16:0/18:1: 91%-98% and PE 16:0/18:2: 94%-103%) and extraction recovery (PE 16:0/18:1: 95%-106% and PE 16:0/18:2: 92%-102%) exceeding 90% over the analytical range. The limit of detection was 5 μg/L. Here we propose a simple SPE LC-MS/MS method for analyzing phospholipids in erythrocytes, which can be easily adopted. © 2018 Wiley Periodicals, Inc.

  17. Joint Bratislava–Prague studies of radiocarbon and uranium in the environment using accelerator mass spectrometry and radiometric methods

    Czech Academy of Sciences Publication Activity Database

    Povinec, P. P.; Světlík, Ivo; Ješkovský, M.; Sivo, A.; John, J.; Špendlíková, I.; Němec, M.; Kučera, Jan; Richtáriková, M.; Breier, R.; Fejgl, Michal; Černý, Radek

    2015-01-01

    Roč. 304, č. 1 (2015), s. 67-73 ISSN 0236-5731 Institutional support: RVO:61389005 Keywords : Accelerator mass spectrometry * Atmosphere * Environmental radioactivity * Radiocarbon * Tree rings * Uranium Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.983, year: 2015

  18. A versatile mass spectrometry-based method to both identify kinase client-relationships and characterize signaling network topology

    Science.gov (United States)

    While more than a thousand protein kinases (PK) have been identified in the Arabidopsis thaliana genome, relatively little progress has been made towards identifying their individual client proteins. Herein we describe use of a mass spectrometry-based in vitro phosphorylation strategy, termed Kinase...

  19. Comparative urine analysis by liquid chromatography-mass spectrometry and multivariate statistics : Method development, evaluation, and application to proteinuria

    NARCIS (Netherlands)

    Kemperman, Ramses F. J.; Horvatovich, Peter L.; Hoekman, Berend; Reijmers, Theo H.; Muskiet, Frits A. J.; Bischoff, Rainer

    2007-01-01

    We describe a platform for the comparative profiling of urine using reversed-phase liquid chromatography-mass spectrometry (LC-MS) and multivariate statistical data analysis. Urinary compounds were separated by gradient elution and subsequently detected by electrospray Ion-Trap MS. The lower limit

  20. A flow-injection mass spectrometry fingerprinting method for authentication and quality assessment of Scutellaria lateriflora-based dietary supplements

    Science.gov (United States)

    Identification and differentiation of anthocyanins and non-anthocyanin compounds in natural products can be very difficult by mass spectrometry. Using a ultra-violet/visible detector can be helpful, but not fool-proof, and it requires an additional detector. To solve the problem, a fast and reliab...

  1. Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone

    DEFF Research Database (Denmark)

    Jensen, Marie Aarrebo; Hansen, Åse Marie; Abrahamsson, Peter

    2011-01-01

    saliva. We used liquid-liquid extraction (LLE) followed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS) recorded in positive ion mode. Saliva samples were collected by spitting directly into tubes and 250 µL were used for analysis. The limits of detection were 4...

  2. Characteristics of Ir/Au transition edge sensor

    International Nuclear Information System (INIS)

    Kunieda, Yuichi; Ohno, Masashi; Nakazawa, Masaharu; Takahashi, Hiroyuki; Fukuda, Daiji; Ohkubo, Masataka

    2004-01-01

    A new type of microcalorimeter has been developed using a transition edge sensor (TES) and an electro-thermal feedback (ETF) method to achieve higher energy resolution and higher count rate. We are developing a superconducting Ir-based transition edge sensor (TES) microcalorimeters. To improve thermal conductivity and achieve higher energy resolution with an Ir-TES, we fabricated an Ir/Au bilayer TES by depositing gold on Ir and investigated the influence of intermediate between superconducting and normal states at the transition edge for signal responses by microscopic observation in the Ir/Au-TES. (T. Tanaka)

  3. Mass Spectrometry Imaging under Ambient Conditions

    Science.gov (United States)

    Wu, Chunping; Dill, Allison L.; Eberlin, Livia S.; Cooks, R. Graham; Ifa, Demian R.

    2012-01-01

    Mass spectrometry imaging (MSI) has emerged as an important tool in the last decade and it is beginning to show potential to provide new information in many fields owing to its unique ability to acquire molecularly specific images and to provide multiplexed information, without the need for labeling or staining. In MSI, the chemical identity of molecules present on a surface is investigated as a function of spatial distribution. In addition to now standard methods involving MSI in vacuum, recently developed ambient ionization techniques allow MSI to be performed under atmospheric pressure on untreated samples outside the mass spectrometer. Here we review recent developments and applications of MSI emphasizing the ambient ionization techniques of desorption electrospray ionization (DESI), laser ablation electrospray ionization (LAESI), probe electrospray ionization (PESI), desorption atmospheric pressure photoionization (DAPPI), femtosecond laser desorption ionization (fs-LDI), laser electrospray mass spectrometry (LEMS), infrared laser ablation metastable-induced chemical ionization (IR-LAMICI), liquid microjunction surface sampling probe mass spectrometry (LMJ-SSP MS), nanospray desorption electrospray ionization (nano-DESI), and plasma sources such as the low temperature plasma (LTP) probe and laser ablation coupled to flowing atmospheric-pressure afterglow (LA-FAPA). Included are discussions of some of the features of ambient MSI including the ability to implement chemical reactions with the goal of providing high abundance ions characteristic of specific compounds of interest and the use of tandem mass spectrometry to either map the distribution of targeted molecules with high specificity or to provide additional MS information in the structural identification of compounds. We also describe the role of bioinformatics in acquiring and interpreting the chemical and spatial information obtained through MSI, especially in biological applications for tissue

  4. Neutron spectrometry by means of threshold detectors - Neutron spectrometry by means of activation detectors. Studies of the method of approximation by polygonal function. Application to dose determination

    International Nuclear Information System (INIS)

    Bricka, M.

    1962-03-01

    This report addresses the problem of determination of neutron spectrum by using a set of detectors. The spectrum approximation method based on a polygonal function is more particularly studied. The author shows that the coefficients of the usual mathematical model can be simply formulated and assessed. The study of spectra approximation by a polygonal function shows that dose can be expressed by a linear function of the activity of the different detectors [fr

  5. Direct measuring of single-cycle mid-IR light bullets path length in LiF by the laser coloration method

    Directory of Open Access Journals (Sweden)

    Chekalin Sergey

    2017-01-01

    Full Text Available A colour-centre structure formed in a LiF crystal under filamentation of a femtosecond mid-IR laser pulse with a power slightly exceeding the critical power for self-focusing has been experimentally and theoretically investigated. A single-cycle light bullet was recorded for the first time by observation of strictly periodic oscillations for the density of the color centers induced in an isotropic LiF crystal under filamentation of a laser beam with a wavelength tuned in the range from 2600 to 3900 nm, which is due to the periodic change in the light field amplitude in the light bullet formed under filamentation under propagation in dispersive medium. The light bullet path length was not more than one millimeter.

  6. Mesoporous silica nanoparticle supported PdIr bimetal catalyst for selective hydrogenation, and the significant promotional effect of Ir

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hui; Huang, Chao; Yang, Fan [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Yang, Xu [Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Du, Li [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China); Liao, Shijun, E-mail: chsjliao@scut.edu.cn [The Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou (China)

    2015-12-01

    Graphical abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction caused by the addition of Ir. - Highlights: • Mesoporous nanoparticles were synthesized and used as support for metal catalyst. • PdIr bimetallic catalyst exhibited significantly improved hydrogenation activity. • The strong promotion of Ir was recognized firstly and investigated intensively. • PdIr exhibits 18 times higher activity than Pd to the hydrogenation of nitrobenzene. - Abstract: A mesoporous silica nanoparticle (MSN) supported bimetal catalyst, PdIr/MSN, was prepared by a facile impregnation and hydrogen reduction method. The strong promotional effect of Ir was observed and thoroughly investigated. At the optimal molar ratio of Ir to Pd (N{sub Ir}/N{sub Pd} = 0.1), the activity of PdIr{sub 0.1}/MSN was up to eight times and 28 times higher than that of monometallic Pd/MSN and Ir/MSN, respectively. The catalysts were characterized comprehensively by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and hydrogen temperature programmed reduction, which revealed that the promotional effect of Ir may be due to the enhanced dispersion of active components on the MSN, and to the intensified Pd–Ir electronic interaction

  7. Gamma-ray spectrometry method used for radioactive waste drums characterization for final disposal at National Repository for Low and Intermediate Radioactive Waste--Baita, Romania.

    Science.gov (United States)

    Done, L; Tugulan, L C; Dragolici, F; Alexandru, C

    2014-05-01

    The Radioactive Waste Management Department from IFIN-HH, Bucharest, performs the conditioning of the institutional radioactive waste in concrete matrix, in 200 l drums with concrete shield, for final disposal at DNDR - Baita, Bihor county, in an old exhausted uranium mine. This paper presents a gamma-ray spectrometry method for the characterization of the radioactive waste drums' radionuclides content, for final disposal. In order to study the accuracy of the method, a similar concrete matrix with Portland cement in a 200 l drum was used. © 2013 The Authors. Published by Elsevier Ltd All rights reserved.

  8. Application of time-of-flight mass spectrometry with laser-based photoionization methods for analytical pyrolysis of PVC

    Energy Technology Data Exchange (ETDEWEB)

    Streibel, T.; Muehlberger, F. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany); Adam, T.; Zimmermann, R. [Augsburg Univ. (Germany); Cao, L. [National Center for Iron and Steel, Beijing, BJ (China)

    2004-09-15

    Chlorinated benzenes and phenols generated from PVC pyrolysis are known to be precursors of PCDD/F formation. Therefore, selective and sensitive monitoring of these substances during PVC pyrolysis processes on an on-line, real-time basis could be very useful for the understanding of PCDD/F formation pathways. In this study, we investigated the pyrolysis gas from PVC samples derived from steel recycling by means of simultaneous single photon ionization/resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (SPI/REMPI-TOFMS). The application of these soft photo-ionization techniques in mass spectrometry enables a fast and comprehensive analysis of this complex matrix without generating fragment ions, which would interfere with molecule ions making interpretation of the obtained mass spectra very difficult.

  9. Structural analysis of isomeric chondroitin sulfate oligosaccharides using regioselective 6-O-desulfation method and tandem mass spectrometry.

    Science.gov (United States)

    Chen, Shu-Ting; Her, Guor-Rong

    2014-09-16

    A strategy based on a regioselective 6-O-desulfation reaction and negative ion electrospray ionization tandem mass spectrometry (ESI-MS(n)) was developed for the structural delineation of isomeric chondroitin sulfate oligosaccharides. Product ions resulting from the glycosidic cleavage provided information about the number of sulfate groups in each sugar residue. After the regioselective 6-O-desulfation reaction, the number of sulfate groups on each residue was obtained using a tandem mass spectrometry analysis of the reaction product. The sulfation pattern could be obtained based on the product ions of analytes before and after the desulfation reaction. The strategy was demonstrated using a series of tetrasaccharides prepared from shark cartilage chondroitin sulfate D. Among the 12 identified tetrasaccharides, six structures had not been reported before. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. A method for the complete analysis of NORM building materials by γ-ray spectrometry using HPGe detectors.

    Science.gov (United States)

    Quintana, B; Pedrosa, M C; Vázquez-Canelas, L; Santamaría, R; Sanjuán, M A; Puertas, F

    2018-04-01

    A methodology including software tools for analysing NORM building materials and residues by low-level gamma-ray spectrometry has been developed. It comprises deconvolution of gamma-ray spectra using the software GALEA with focus on the natural radionuclides and Monte Carlo simulations for efficiency and true coincidence summing corrections. The methodology has been tested on a range of building materials and validated against reference materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Synthesis, X-ray diffraction method, spectroscopic characterization (FT-IR, 1H and 13C NMR), antimicrobial activity, Hirshfeld surface analysis and DFT computations of novel sulfonamide derivatives

    Science.gov (United States)

    Demircioğlu, Zeynep; Özdemir, Fethi Ahmet; Dayan, Osman; Şerbetçi, Zafer; Özdemir, Namık

    2018-06-01

    Synthesized compounds of N-(2-aminophenyl)benzenesulfonamide 1 and (Z)-N-(2-((2-nitrobenzylidene)amino)phenyl)benzenesulfonamide 2 were characterized by antimicrobial activity, FT-IR, 1H and 13C NMR. Two new Schiff base ligands containing aromatic sulfonamide fragment of (Z)-N-(2-((3-nitrobenzylidene)amino)phenyl)benzenesulfonamide 3 and (Z)-N-(2-((4-nitrobenzylidene)amino)phenyl)benzenesulfonamide 4 were synthesized and investigated by spectroscopic techniques including 1H and 13C NMR, FT-IR, single crystal X-ray diffraction, Hirshfeld surface, theoretical method analyses and by antimicrobial activity. The molecular geometry obtained from the X-ray structure determination was optimized Density Functional Theory (DFT/B3LYP) method with the 6-311++G(d,p) basis set in ground state. From the optimized geometry of the molecules of 3 and 4, the geometric parameters, vibrational wavenumbers and chemical shifts were computed. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP 6-311G++(d,p) was a successful choice. After a successful optimization, frontier molecular orbitals, chemical activity, non-linear optical properties (NLO), molecular electrostatic mep (MEP), Mulliken population method, natural population analysis (NPA) and natural bond orbital analysis (NBO), which cannot be obtained experimentally, were calculated and investigated.

  12. Mass spectrometry at the Pittsburgh conference

    International Nuclear Information System (INIS)

    Borman, S.

    1987-01-01

    Each year analytical chemists flock to the Pittsburgh Conference to learn about the latest trends in analytical instrumentation. In this Focus, a number of prominent mass spectroscopists who attended this year's meeting in Atlantic City, NJ, discuss their perceptions of current developments in the field of mass spectrometry (MS). In the June 1 issue of Analytical Chemistry, the authors coverage of the Pittsburgh Conferences continues with a follow-up article on specific developments in hyphenated mass spectrometry - primarily liquid chromatography - MS (LC/MS) and gas chromatography - infrared spectrometry MS (GC/IR/MS)

  13. Influences of Normalization Method on Biomarker Discovery in Gas Chromatography-Mass Spectrometry-Based Untargeted Metabolomics: What Should Be Considered?

    Science.gov (United States)

    Chen, Jiaqing; Zhang, Pei; Lv, Mengying; Guo, Huimin; Huang, Yin; Zhang, Zunjian; Xu, Fengguo

    2017-05-16

    Data reduction techniques in gas chromatography-mass spectrometry-based untargeted metabolomics has made the following workflow of data analysis more lucid. However, the normalization process still perplexes researchers, and its effects are always ignored. In order to reveal the influences of normalization method, five representative normalization methods (mass spectrometry total useful signal, median, probabilistic quotient normalization, remove unwanted variation-random, and systematic ratio normalization) were compared in three real data sets with different types. First, data reduction techniques were used to refine the original data. Then, quality control samples and relative log abundance plots were utilized to evaluate the unwanted variations and the efficiencies of normalization process. Furthermore, the potential biomarkers which were screened out by the Mann-Whitney U test, receiver operating characteristic curve analysis, random forest, and feature selection algorithm Boruta in different normalized data sets were compared. The results indicated the determination of the normalization method was difficult because the commonly accepted rules were easy to fulfill but different normalization methods had unforeseen influences on both the kind and number of potential biomarkers. Lastly, an integrated strategy for normalization method selection was recommended.

  14. Analytical mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  15. Analytical mass spectrometry. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  16. Efficacy and compatibility with mass spectrometry of methods for elution of proteins from sodium dodecyl sulfate-polyacrylamide gels and polyvinyldifluoride membranes

    DEFF Research Database (Denmark)

    Jørgensen, C.S.; Jagd, M.; Sørensen, B.K.

    2004-01-01

    projects. As a result of this, methods for postelectrophoretic protein characterization are of Great interest as exemplified by in situ protease digestion combined with mass spectrometry (MS), which is the method of choice for identification of proteins. In this study we have developed and compared methods...... for recovering intact proteins from polyacrylamide gels and electroblotting membranes to define efficient methods compatible with MS. These methods complement in situ digestion protocols and allow determination of the molecular mass of whole proteins separated by SDS-PAGE. Passive elution of proteins from SDS......-PAGE gels was efficient only in the presence of SDS, whereas electroelution was achieved using butTers without SDS. Surface-enhanced laser desorption/ionization MS (SELDI-MS) analysis of proteins eluted in the presence of SIDS was possible using ion exchange ProteinChip arrays for concentration of sample...

  17. Development of methods for activity determination for radionuclides with double decay emission β- β+ / electron capture - application to the standardization of 192Ir, 152Eu and 186 Re

    International Nuclear Information System (INIS)

    Hilario, Katia Aparecida Fonseca

    2002-01-01

    In the present work alternative procedures have been developed for standardization of radionuclides with double decay, β - β + / electron capture using the 4πβ-γ coincidence technique, applying different systems. Two 4πβ-γ coincidence systems were used: one with a 4π gas-flow proportional counter coupled to a pair of NaI(Tl) scintillators and the other one with the same type of proportional counter coupled to HPGe detector. The radionuclides selected for this standardization, due to great interest in nuclear medicine, detector calibration and industrial radiography, were 192 Ir, 152 Eu and 186 Re. The first and the second were part of international comparisons sponsored by the Bureau International des Poids et Mesures (BIPM), France, who supplied the radioactive solution. For 186 Re, the gamma-ray emission probability per decay was measured by means REGe spectrometer system, previously calibrated with standard ampoules. All the uncertainties involved were treated rigorously, by means of covariance analysis. (author)

  18. FT-Raman, FT-IR spectra and total energy distribution of 3-pentyl-2,6-diphenylpiperidin-4-one: DFT method.

    Science.gov (United States)

    Subashchandrabose, S; Saleem, H; Erdogdu, Y; Rajarajan, G; Thanikachalam, V

    2011-11-01

    FT-Raman and FT-IR spectra were recorded for 3-pentyl-2,6-diphenylpiperidin-4-one (PDPO) sample in solid state. The equilibrium geometries, harmonic vibrational frequencies, infrared and the Raman scattering intensities were computed using DFT/6-31G(d,p) level. Results obtained at this level of theory were used for a detailed interpretation of the infrared and Raman spectra, based on the total energy distribution (TED) of the normal modes. Molecular parameters such as bond lengths, bond angles and dihedral angles were calculated and compared with X-ray diffraction data. This comparison was good agreement. The intra-molecular charge transfer was calculated by means of natural bond orbital analysis (NBO). Hyperconjugative interaction energy was more during the π-π* transition. Energy gap of the molecule was found using HOMO and LUMO calculation, hence the less band gap, which seems to be more stable. Atomic charges of the carbon, nitrogen and oxygen were calculated using same level of calculation. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Application of fiber-optic attenuated total reflection-FT-IR methods for in situ characterization of protein delivery systems in real time.

    Science.gov (United States)

    McFearin, Cathryn L; Sankaranarayanan, Jagadis; Almutairi, Adah

    2011-05-15

    A fiber-optic coupled attenuated total reflection (ATR)-FT-IR spectroscopy technique was applied to the study of two different therapeutic delivery systems, acid degradable hydrogels and nanoparticles. Real time exponential release of a model protein, human serum albumin (HSA), was observed from two different polymeric hydrogels formulated with a pH sensitive cross-linker. Spectroscopic examination of nanoparticles formulated with an acid degradable polymer shell and encapsulated HSA exhibited vibrational signatures characteristic of both particle and payload when exposed to lowered pH conditions, demonstrating the ability of this methodology to simultaneously measure phenomena arising from a system with a mixture of components. In addition, thorough characterization of these pH sensitive delivery vehicles without encapsulated protein was also accomplished in order to separate the effects of the payload during degradation. When in situ, real time detection in combination with the ability to specifically identify different components in a mixture without involved sample preparation and minimal sample disturbance is provided, the versatility and suitability of this type of experiment for research in the pharmaceutical field is demonstrated.

  20. IR and the Earth

    DEFF Research Database (Denmark)

    Corry, Olaf; Stevenson, Hayley

    2017-01-01

    , in the end, one finite interconnected space. Together these two starting points make for the basic conundrum of Inter- national Relations and the Earth: how does a divided world live on a single globe? This introduction first provides an overview of the recent rise of ‘the environment’ in international......, ‘what has the environment ever done for IR?’, before the plan for the rest of the book sketches the content and direction of the ensuing chapters that explore the problematique of International Relations and the Earth....

  1. Bio-analytical method development and validation of Rasagiline by high performance liquid chromatography tandem mass spectrometry detection and its application to pharmacokinetic study

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Konda

    2012-10-01

    Full Text Available The most suitable bio-analytical method based on liquid–liquid extraction has been developed and validated for quantification of Rasagiline in human plasma. Rasagiline-13C3 mesylate was used as an internal standard for Rasagiline. Zorbax Eclipse Plus C18 (2.1 mm×50 mm, 3.5 μm column provided chromatographic separation of analyte followed by detection with mass spectrometry. The method involved simple isocratic chromatographic condition and mass spectrometric detection in the positive ionization mode using an API-4000 system. The total run time was 3.0 min. The proposed method has been validated with the linear range of 5–12000 pg/mL for Rasagiline. The intra-run and inter-run precision values were within 1.3%–2.9% and 1.6%–2.2% respectively for Rasagiline. The overall recovery for Rasagiline and Rasagiline-13C3 mesylate analog was 96.9% and 96.7% respectively. This validated method was successfully applied to the bioequivalence and pharmacokinetic study of human volunteers under fasting condition. Keywords: High performance liquid chromatography, Mass spectrometry, Rasagiline, Liquid–liquid extraction

  2. Liquid chromatography-tandem mass spectrometry method for determination of panel of neurotransmitters in cerebrospinal fluid from the rat model for tauopathy.

    Science.gov (United States)

    Kovac, Andrej; Somikova, Zuzana; Zilka, Norbert; Novak, Michal

    2014-02-01

    Alzheimer's disease (AD) is still being recognized today as an unmet medical need. Currently, there is no cure and early preclinical diagnostic assay available for AD. Therefore much attention is now being directed at the development of novel methods for quantitative determination of AD biomarkers in the cerebrospinal fluid (CSF). Here, we describe the liquid chromatography-tandem mass spectrometry method for determination of 5-hydroxytryptamine (SER), 5-hydroxyindoleacetic acid (5-HIAA), homovanilic acid (HVA), noradrenaline (NADR), adrenaline (ADR), dopamine (DA), glutamic acid (Glu), γ-aminobutyric acid (GABA), 3,4-dihydroxyphenylacetic acid (DOPAC) and histamine (HIS) in cerebrospinal fluid (CSF) from the rat model for human tauopathy. The benzoyl chloride was used as pre-column derivatization reagents. Neurotransmitters and metabolites were analysed on ultra performance liquid chromatography (UPLC) on C18 column in combination with tandem mass spectrometry. The method is simple, highly sensitive and showed excellent linearity with regression coefficients higher than 0.99. The accuracy was in a range of 93-113% for all analytes. The inter-day precision (n=5 days), expressed as %RSD, was in a range 2-10% for all analytes. Using this method we detected significant changes of CSF levels of two important neurotransmitters/metabolites, ADR and 5-HIAA, which correlates with progression of neurodegeneration in our animal model. © 2013 Published by Elsevier B.V.

  3. Ambient ionization mass spectrometry

    International Nuclear Information System (INIS)

    Lebedev, A T

    2015-01-01

    Ambient ionization mass spectrometry emerged as a new scientific discipline only about ten years ago. A considerable body of information has been reported since that time. Keeping the sensitivity, performance and informativity of classical mass spectrometry methods, the new approach made it possible to eliminate laborious sample preparation procedures and triggered the development of miniaturized instruments to work directly in the field. The review concerns the theoretical foundations and design of ambient ionization methods. Their advantages and drawbacks, as well as prospects for application in chemistry, biology, medicine, environmetal analysis, etc., are discussed. The bibliography includes 194 references

  4. Some analytical aspects of the Moessbauer spectrometry

    International Nuclear Information System (INIS)

    Meisel, W.

    1975-01-01

    Analytical applications of Moessbauer spectrometry are reviewed. Various methods of analysis (qualitative, semiquantitative and quantitative) using the Moessbauer effect are dealt with. Sensitivity and accuracy of Moessbauer spectrometry in analytical applications are discussed. (Z.S.)

  5. Novel liquid chromatography–mass spectrometry method for sensitive determination of the mustard allergen Sin a 1 in food

    OpenAIRE

    Alvarez-Llamas, Gloria; Maes, Xavier; Muñoz-García, Esther; Villalba, Mayte; Rodríguez, Rosalía; Pérez-Gordo, Marina; Vivanco, Fernando; Pérez-Gordo, Carlos; Cuesta-Herranz, Javier

    2015-01-01

    Mustard is a condiment added to a variety of foodstuffs and a frequent cause of food allergy. A new strategy for the detection of mustard allergen in food products is presented. The methodology is based on liquid chromatography analysis coupled to mass spectrometry. Mustard allergen Sin a 1 was purified from yellow mustard seeds. Sin a 1 was detected with a total of five peptides showing a linear response (lowest LOD was 5 ng). Sin a 1 was detected in mustard sauces and salty biscuit (19 ± 3 ...

  6. Alpha spectrometry and secondary ion mass spectrometry of thorium

    International Nuclear Information System (INIS)

    Strisovska, Jana; Kuruc, Jozef; Galanda, Dusan; Matel, Lubomir; Velic, Dusan; Aranyosiova, Monika

    2009-01-01

    A sample of thorium content on steel discs was prepared by electrodeposition with a view to determining the natural thorium isotope. Thorium was determined by alpha spectrometry and by secondary ion mass spectrometry and the results of the two methods were compared

  7. Mass spectrometry in clinical chemistry

    International Nuclear Information System (INIS)

    Pettersen, J.E.

    1977-01-01

    A brief description is given of the functional elements of a mass spectrometer and of some currently employed mass spectrometric techniques, such as combined gas chromatography-mass spectrometry, mass chromatography, and selected ion monitoring. Various areas of application of mass spectrometry in clinical chemistry are discussed, such as inborn errors of metabolism and other metabolic disorders, intoxications, quantitative determinations of drugs, hormones, gases, and trace elements, and the use of isotope dilution mass spectrometry as a definitive method for the establishment of true values for concentrations of various compounds in reference sera. It is concluded that mass spectrometry is of great value in clinical chemistry. (Auth.)

  8. Detailed IR aperture measurements

    CERN Document Server

    Bruce, Roderik; Garcia Morales, Hector; Giovannozzi, Massimo; Hermes, Pascal Dominik; Mirarchi, Daniele; Quaranta, Elena; Redaelli, Stefano; Rossi, Carlo; Skowronski, Piotr Krzysztof; Wretborn, Sven Joel; CERN. Geneva. ATS Department

    2016-01-01

    MD 1673 was carried out on October 5 2016, in order to investigate in more detail the available aperture in the LHC high-luminosity insertions at 6.5 TeV and β∗=40 cm. Previous aperture measurements in 2016 during commissioning had shown that the available aperture is at the edge of protection, and that the aperture bottleneck at β∗=40 cm in certain cases is found in the separation plane instead of in the crossing plane. Furthermore, the bottlenecks were consistently found in close to the upstream end of Q3 on the side of the incoming beam, and not in Q2 on the outgoing beam as expected from calculations. Therefore, this MD aimed at measuring IR1 and IR5 separately (at 6.5 TeV and β∗=40 cm, for 185 µrad half crossing angle), to further localize the bottlenecks longitudinally using newly installed BLMs, investigate the difference in aperture between Q2 and Q3, and to see if any aperture can be gained using special orbit bumps.

  9. Comparison of High Performance Liquid Chromatography with Fluorescence Detector and with Tandem Mass Spectrometry methods for detection and quantification of Ochratoxin A in green and roasted coffee beans

    Directory of Open Access Journals (Sweden)

    Raquel Duarte da Costa Cunha Bandeira

    2013-12-01

    Full Text Available Two analytical methods for the determination and confirmation of ochratoxin A (OTA in green and roasted coffee samples were compared. Sample extraction and clean-up were based on liquid-liquid phase extraction and immunoaffinity column. The detection of OTA was carried out with the high performance liquid chromatography (HPLC combined either with fluorescence detection (FLD, or positive electrospray ionization (ESI+ coupled with tandem mass spectrometry (MS-MS. The results obtained with the LC-ESI-MS/MS were specific and more sensitive, with the advantages in terms of unambiguous analyte identification, when compared with the HPLC-FLD.

  10. Study on IR Properties of Reduced Graphene Oxide

    Science.gov (United States)

    Ma, Deyue; Li, Xiaoxia; Guo, Yuxiang; Zeng, Yurun

    2018-01-01

    Firstly, the reduced graphene oxide was prepared by modified hummer method and characterized. Then, the complex refractive index of reduced graphene oxide in IR band was tested and its IR absorption and radiation properties were researched by correlated calculation. The results show that reduced graphene oxide prepared by hummer method are multilayered graphene with defects and functional groups on its surface. Its absorption in near and far IR bands is strong, but it’s weaker in middle IR band. At the IR atmosphere Window, its normal spectral emissivity decreases with wavelength increasing, and its total normal spectral emissivity in 3 ∼ 5μm and 8 ∼ 14μm are 0.75 and 0.625, respectively. Therefore, reduced graphene oxide can be used as IR absorption and coating materials and have a great potential in microwave and infrared compatible materials.

  11. Development of QuEChERS-based extraction and liquid chromatography-tandem mass spectrometry method for quantifying flumethasone residues in beef muscle.

    Science.gov (United States)

    Park, Ki Hun; Choi, Jeong-Heui; Abd El-Aty, A M; Cho, Soon-Kil; Park, Jong-Hyouk; Kwon, Ki Sung; Park, Hee Ra; Kim, Hyung Soo; Shin, Ho-Chul; Kim, Mi Ra; Shim, Jae-Han

    2012-12-01

    A rapid, specific, and sensitive method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM) was developed and validated to quantify flumethasone residues in beef muscle. Methods were compared between the original as well as the EN quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction. Good linearity was achieved at concentration levels of 5-30 μg/kg. Estimated recovery rates at spiking levels of 5 and 10 μg/kg ranged from 72.1 to 84.6%, with relative standard deviations (RSDs)noise ratios (S/Ns) of 3 and 10, respectively. The method was successfully applied to analyze real samples obtained from large markets throughout the Korean Peninsula. The method proved to be sensitive and reliable and, thus, rendered an appropriate means for residue analysis studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. A Variety of Activation Methods Employed in 'Activated-Ion' Electron Capture Dissociation Mass Spectrometry: A Test against Bovine Ubiquitin 7+ Ions

    International Nuclear Information System (INIS)

    Oh, Han Bin; McLafferty, Fred W.

    2006-01-01

    Fragmentation efficiencies of various 'activated-ion' electron capture dissociation (AI-ECD) methods are compared for a model system of bovine ubiquitin 7+ cations. In AI-ECD studies, sufficient internal energy was given to protein cations prior to ECD application using IR laser radiation, collisions, blackbody radiation, or in-beam collisions, in turn. The added energy was utilized in increasing the population of the precursor ions with less intra-molecular noncovalent bonds or enhancing thermal fluctuations of the protein cations. Removal of noncovalent bonds resulted in extended structures, which are ECD friendly. Under their best conditions, a variety of activation methods showed a similar effectiveness in ECD fragmentation. In terms of the number of fragmented inter-residue bonds, IR laser/blackbody infrared radiation and 'in-beam' activation were almost equally efficient with ∼70% sequence coverage, while collisions were less productive. In particular, 'in-beam' activation showed an excellent effectiveness in characterizing a pre-fractionated single kind of protein species. However, its inherent procedure did not allow for isolation of the protein cations of interest

  13. Discrimination of Chinese Sauce liquor using FT-IR and two-dimensional correlation IR spectroscopy

    Science.gov (United States)

    Sun, Su-Qin; Li, Chang-Wen; Wei, Ji-Ping; Zhou, Qun; Noda, Isao

    2006-11-01

    We applied the three-step IR macro-fingerprint identification method to obtain the IR characteristic fingerprints of so-called Chinese Sauce liquor (Moutai liquor and Kinsly liquor) and a counterfeit Moutai. These fingerprints can be used for the identification and discrimination of similar liquor products. The comparison of their conventional IR spectra, as the first step of identification, shows that the primary difference in Sauce liquor is the intensity of characteristic peaks at 1592 and 1225 cm -1. The comparison of the second derivative IR spectra, as the second step of identification, shows that the characteristic absorption in 1400-1800 cm -1 is substantially different. The comparison of 2D-IR correlation spectra, as the third and final step of identification, can discriminate the liquors from another direction. Furthermore, the method was successfully applied to the discrimination of a counterfeit Moutai from the genuine Sauce liquor. The success of the three-step IR macro-fingerprint identification to provide a rapid and effective method for the identification of Chinese liquor suggests the potential extension of this technique to the identification and discrimination of other wine and spirits, as well.

  14. Development of a methodology for the detection of Ra226 in large volumes of water by gamma spectrometry; modification and validation of the method for detection and quantification of Ra226 in small volumes of water by alpha spectrometry, used by the Centro de Investigacion en Ciencias Atomicas, Nucleares y Moleculares (CICANUM, UCR)

    International Nuclear Information System (INIS)

    Molina Porras, Arnold

    2011-01-01

    The test method has been validated for quantifying the specific activity of Ra 226 in water alpha spectrometry. The CICANUM has used this method as part of the proposed harmonization of methods ARCAL (IAEA). The method is based on a first separation and preconcentration of Ra 226 by coprecipitation and subsequent MnO 2 micro precipitation as Ba (Ra) SO 4 . Samples were prepared and then was performed the counting by alpha spectrometry. A methodology of radio sampling for large volumes of water was tested in parallel, using acrylic fibers impregnated with manganese oxide (IV) to determine the amount of Ra 226 present by gamma spectrometry. Small-scale tests, have determined that the best way to prepare the fiber is the reference method found in the literature and using the oven at 60 degrees Celsius. (author) [es

  15. A Machine Learning Application Based in Random Forest for Integrating Mass Spectrometry-Based Metabolomic Data: A Simple Screening Method for Patients With Zika Virus

    Directory of Open Access Journals (Sweden)

    Carlos Fernando Odir Rodrigues Melo

    2018-04-01

    Full Text Available Recent Zika outbreaks in South America, accompanied by unexpectedly severe clinical complications have brought much interest in fast and reliable screening methods for ZIKV (Zika virus identification. Reverse-transcriptase polymerase chain reaction (RT-PCR is currently the method of choice to detect ZIKV in biological samples. This approach, nonetheless, demands a considerable amount of time and resources such as kits and reagents that, in endemic areas, may result in a substantial financial burden over affected individuals and health services veering away from RT-PCR analysis. This study presents a powerful combination of high-resolution mass spectrometry and a machine-learning prediction model for data analysis to assess the existence of ZIKV infection across a series of patients that bear similar symptomatic conditions, but not necessarily are infected with the disease. By using mass spectrometric data that are inputted with the developed decision-making algorithm, we were able to provide a set of features that work as a “fingerprint” for this specific pathophysiological condition, even after the acute phase of infection. Since both mass spectrometry and machine learning approaches are well-established and have largely utilized tools within their respective fields, this combination of methods emerges as a distinct alternative for clinical applications, providing a diagnostic screening—faster and more accurate—with improved cost-effectiveness when compared to existing technologies.

  16. A Machine Learning Application Based in Random Forest for Integrating Mass Spectrometry-Based Metabolomic Data: A Simple Screening Method for Patients With Zika Virus.

    Science.gov (United States)

    Melo, Carlos Fernando Odir Rodrigues; Navarro, Luiz Claudio; de Oliveira, Diogo Noin; Guerreiro, Tatiane Melina; Lima, Estela de Oliveira; Delafiori, Jeany; Dabaja, Mohamed Ziad; Ribeiro, Marta da Silva; de Menezes, Maico; Rodrigues, Rafael Gustavo Martins; Morishita, Karen Noda; Esteves, Cibele Zanardi; de Amorim, Aline Lopes Lucas; Aoyagui, Caroline Tiemi; Parise, Pierina Lorencini; Milanez, Guilherme Paier; do Nascimento, Gabriela Mansano; Ribas Freitas, André Ricardo; Angerami, Rodrigo; Costa, Fábio Trindade Maranhão; Arns, Clarice Weis; Resende, Mariangela Ribeiro; Amaral, Eliana; Junior, Renato Passini; Ribeiro-do-Valle, Carolina C; Milanez, Helaine; Moretti, Maria Luiza; Proenca-Modena, Jose Luiz; Avila, Sandra; Rocha, Anderson; Catharino, Rodrigo Ramos

    2018-01-01

    Recent Zika outbreaks in South America, accompanied by unexpectedly severe clinical complications have brought much interest in fast and reliable screening methods for ZIKV (Zika virus) identification. Reverse-transcriptase polymerase chain reaction (RT-PCR) is currently the method of choice to detect ZIKV in biological samples. This approach, nonetheless, demands a considerable amount of time and resources such as kits and reagents that, in endemic areas, may result in a substantial financial burden over affected individuals and health services veering away from RT-PCR analysis. This study presents a powerful combination of high-resolution mass spectrometry and a machine-learning prediction model for data analysis to assess the existence of ZIKV infection across a series of patients that bear similar symptomatic conditions, but not necessarily are infected with the disease. By using mass spectrometric data that are inputted with the developed decision-making algorithm, we were able to provide a set of features that work as a "fingerprint" for this specific pathophysiological condition, even after the acute phase of infection. Since both mass spectrometry and machine learning approaches are well-established and have largely utilized tools within their respective fields, this combination of methods emerges as a distinct alternative for clinical applications, providing a diagnostic screening-faster and more accurate-with improved cost-effectiveness when compared to existing technologies.

  17. Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry.

    Science.gov (United States)

    Duemichen, E; Braun, U; Senz, R; Fabian, G; Sturm, H

    2014-08-08

    For analysis of the gaseous thermal decomposition products of polymers, the common techniques are thermogravimetry, combined with Fourier transformed infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS). These methods offer a simple approach to the decomposition mechanism, especially for small decomposition molecules. Complex spectra of gaseous mixtures are very often hard to identify because of overlapping signals. In this paper a new method is described to adsorb the decomposition products during controlled conditions in TGA on solid-phase extraction (SPE) material: twisters. Subsequently the twisters were analysed with thermal desorption gas chromatography mass spectrometry (TDS-GC-MS), which allows the decomposition products to be separated and identified using an MS library. The thermoplastics polyamide 66 (PA 66) and polybutylene terephthalate (PBT) were used as example polymers. The influence of the sample mass and of the purge gas flow during the decomposition process was investigated in TGA. The advantages and limitations of the method were presented in comparison to the common analysis techniques, TGA-FTIR and TGA-MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Laboratory of acceleration mass spectrometry

    International Nuclear Information System (INIS)

    Hybler, P.; Chrapan, J.

    2002-01-01

    In this paper authors describe the principle of the method of acceleration mass spectrometry and the construction plans of this instrument at the Faculty of ecology and environmental sciences in Banska Stiavnica. Using of this instrument for radiocarbon dating is discussed. A review of laboratories with acceleration mass spectrometry is presented

  19. Room temperature mid-IR single photon spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2012-01-01

    Spectral imaging and detection of mid-infrared (mid-IR) wavelengths are emerging as an enabling technology of great technical and scientific interest; primarily because important chemical compounds display unique and strong mid-IR spectral fingerprints revealing valuable chemical information. Whi...... 20 % for polarized incoherent light at 3 \\mum. The proposed method is relevant for existing and new mid-IR applications like gas analysis and medical diagnostics....

  20. The Introduction of an Undergraduate Interventional Radiology (IR) Curriculum: Impact on Medical Student Knowledge and Interest in IR

    International Nuclear Information System (INIS)

    Shaikh, M.; Shaygi, B.; Asadi, H.; Thanaratnam, P.; Pennycooke, K.; Mirza, M.; Lee, M.

    2016-01-01

    IntroductionInterventional radiology (IR) plays a vital role in modern medicine, with increasing demand for services, but with a shortage of experienced interventionalists. The aim of this study was to determine the impact of a recently introduced IR curriculum on perception, knowledge, and interest of medical students regarding various aspects of IR.MethodsIn 2014, an anonymous web-based questionnaire was sent to 309 4th year medical students in a single institution within an EU country, both before and after delivery of a 10-h IR teaching curriculum.ResultsSeventy-six percent (236/309) of the respondents participated in the pre-IR module survey, while 50 % (157/309) responded to the post-IR module survey. While 62 % (147/236) of the respondents reported poor or no knowledge of IR compared to other medical disciplines in the pre-IR module survey, this decreased to 17 % (27/157) in the post-IR module survey. The correct responses regarding knowledge of selected IR procedures improved from 70 to 94 % for venous access, 78 to 99 % for uterine fibroid embolization, 75 to 97 % for GI bleeding embolization, 60 to 92 % for trauma embolization, 71 to 92 % for tumor ablation, and 81 to 94 % for angioplasty and stenting in peripheral arterial disease. With regard to knowledge of IR clinical roles, responses improved from 42 to 59 % for outpatient clinic review of patients and having inpatient beds, 63–76 % for direct patient consultation, and 43–60 % for having regular ward rounds. The number of students who would consider a career in IR increased from 60 to 73 %.ConclusionDelivering an undergraduate IR curriculum increased the knowledge and understanding of various aspects of IR and also the general enthusiasm for pursuing this specialty as a future career choice.

  1. The Introduction of an Undergraduate Interventional Radiology (IR) Curriculum: Impact on Medical Student Knowledge and Interest in IR

    Energy Technology Data Exchange (ETDEWEB)

    Shaikh, M. [Bradford Royal Infirmary, Department of Radiology, Bradford Teaching Hospital Foundation Trust (United Kingdom); Shaygi, B. [Royal Devon and Exeter Hospital, Interventional Radiology Department (United Kingdom); Asadi, H., E-mail: asadi.hamed@gmail.com; Thanaratnam, P.; Pennycooke, K.; Mirza, M.; Lee, M., E-mail: mlee@rcsi.ie [Beaumont Hospital, Interventional Radiology Service, Department of Radiology (Ireland)

    2016-04-15

    IntroductionInterventional radiology (IR) plays a vital role in modern medicine, with increasing demand for services, but with a shortage of experienced interventionalists. The aim of this study was to determine the impact of a recently introduced IR curriculum on perception, knowledge, and interest of medical students regarding various aspects of IR.MethodsIn 2014, an anonymous web-based questionnaire was sent to 309 4th year medical students in a single institution within an EU country, both before and after delivery of a 10-h IR teaching curriculum.ResultsSeventy-six percent (236/309) of the respondents participated in the pre-IR module survey, while 50 % (157/309) responded to the post-IR module survey. While 62 % (147/236) of the respondents reported poor or no knowledge of IR compared to other medical disciplines in the pre-IR module survey, this decreased to 17 % (27/157) in the post-IR module survey. The correct responses regarding knowledge of selected IR procedures improved from 70 to 94 % for venous access, 78 to 99 % for uterine fibroid embolization, 75 to 97 % for GI bleeding embolization, 60 to 92 % for trauma embolization, 71 to 92 % for tumor ablation, and 81 to 94 % for angioplasty and stenting in peripheral arterial disease. With regard to knowledge of IR clinical roles, responses improved from 42 to 59 % for outpatient clinic review of patients and having inpatient beds, 63–76 % for direct patient consultation, and 43–60 % for having regular ward rounds. The number of students who would consider a career in IR increased from 60 to 73 %.ConclusionDelivering an undergraduate IR curriculum increased the knowledge and understanding of various aspects of IR and also the general enthusiasm for pursuing this specialty as a future career choice.

  2. [Determination of 51 carbamate pesticide residues in vegetables by liquid chromatography-tandem mass spectrometry based on optimization of QuEChERS sample preparation method].

    Science.gov (United States)

    Wang, Lianzhu; Zhou, Yu; Huang, Xiaoyan; Wang, Ruilong; Lin, Zixu; Chen, Yong; Wang, Dengfei; Lin, Dejuan; Xu, Dunming

    2013-12-01

    The raw extracts of six vegetables (tomato, green bean, shallot, broccoli, ginger and carrot) were analyzed using gas chromatography-mass spectrometry (GC-MS) in full scan mode combined with NIST library search to confirm main matrix compounds. The effects of cleanup and adsorption mechanisms of primary secondary amine (PSA) , octadecylsilane (C18) and PSA + C18 on co-extractives were studied by the weight of evaporation residue for extracts before and after cleanup. The suitability of the two versions of QuEChERS method for sample preparation was evaluated for the extraction of 51 carbamate pesticides in the six vegetables. One of the QuEChERS methods was the original un-buffered method published in 2003, and the other was AOAC Official Method 2007.01 using acetate buffer. As a result, the best effects were obtained from using the combination of C18 and PSA for extract cleanup in vegetables. The acetate-buffered version was suitable for the determination of all pesticides except dioxacarb. Un-buffered QuEChERS method gave satisfactory results for determining dioxacarb. Based on these results, the suitable QuEChERS sample preparation method and liquid chromatography-positive electrospray ionization-tandem mass spectrometry under the optimized conditions were applied to determine the 51 carbamate pesticide residues in six vegetables. The analytes were quantified by matrix-matched standard solution. The recoveries at three levels of 10, 20 and 100 microg/kg spiked in six vegetables ranged from 58.4% to 126% with the relative standard deviations of 3.3%-26%. The limits of quantification (LOQ, S/N > or = 10) were 0.2-10 microg/kg except that the LOQs of cartap and thiofanox were 50 microg/kg. The method is highly efficient, sensitive and suitable for monitoring the 51 carbamate pesticide residues in vegetables.

  3. IR-IR Conformation Specific Spectroscopy of Na+(Glucose) Adducts

    Science.gov (United States)

    Voss, Jonathan M.; Kregel, Steven J.; Fischer, Kaitlyn C.; Garand, Etienne

    2018-01-01

    We report an IR-IR double resonance study of the structural landscape present in the Na+(glucose) complex. Our experimental approach involves minimal modifications to a typical IR predissociation setup, and can be carried out via ion-dip or isomer-burning methods, providing additional flexibility to suit different experimental needs. In the current study, the single-laser IR predissociation spectrum of Na+(glucose), which clearly indicates contributions from multiple structures, was experimentally disentangled to reveal the presence of three α-conformers and five β-conformers. Comparisons with calculations show that these eight conformations correspond to the lowest energy gas-phase structures with distinctive Na+ coordination. [Figure not available: see fulltext.

  4. Easy Extraction Method To Evaluate δ13C Vanillin by Liquid Chromatography-Isotopic Ratio Mass Spectrometry in Chocolate Bars and Chocolate Snack Foods.

    Science.gov (United States)

    Bononi, Monica; Quaglia, Giancarlo; Tateo, Fernando

    2015-05-20

    An easy extraction method that permits the use of a liquid chromatography-isotopic ratio mass spectrometry (LC-IRMS) system to evaluate δ(13)C of vanillin in chocolate products and industrial flavorings is presented. The method applies the determination of stable isotopes of carbon to discriminate between natural vanillin from vanilla beans and vanillin from other sources (mixtures from beans, synthesis, or biotechnology). A series of 13 chocolate bars and chocolate snack foods available on the Italian market and 8 vanilla flavorings derived from industrial quality control processes were analyzed. Only 30% of products considered in this work that declared "vanilla" on the label showed data that permitted the declaration "vanilla" according to European Union (EU) Regulation 1334/2008. All samples not citing "vanilla" or "natural flavoring" on the label gave the correct declaration. The extraction method is presented with data useful for statistical evaluation.

  5. Standard test method for isotopic abundance analysis of uranium hexafluoride and uranyl nitrate solutions by multi-collector, inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2014-01-01

    1.1 This test method covers the isotopic abundance analysis of 234U, 235U, 236U and 238U in samples of hydrolysed uranium hexafluoride (UF6) by inductively coupled plasma source, multicollector, mass spectrometry (ICP-MC-MS). The method applies to material with 235U abundance in the range of 0.2 to 6 % mass. This test method is also described in ASTM STP 1344. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  6. On-line immunoaffinity column-liquid chromatography-tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample.

    Science.gov (United States)

    Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

    2006-11-10

    An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

  7. Development and validation of confirmatory method for analysis of nitrofuran metabolites in milk, honey, poultry meat and fish by liquid chromatography-mass spectrometry

    Directory of Open Access Journals (Sweden)

    Fatih Alkan

    2016-03-01

    Full Text Available In this study we have devoloped and validated a confirmatory analysis method for nitrofuran metabolites, which is in accordance with European Commission Decision 2002/657/EC requirements. Nitrofuran metabolites in honey, milk, poultry meat and fish samples were acidic hydrolised followed by derivatisation with nitrobenzaldehyde and liquid-liquid extracted with ethylacetate. The quantitative and confirmative determination of nitrofuran metbolites was performed by liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS in the positive ion mode. In-house method validation was performed and reported data of validation (specificity, linearity, recovery, CCα and CCβ. The advantage of this method is that it avoids the use of clean-up by Solid-Phase Extraction (SPE. Furthermore, low levels of nitrofuran metabolites are detectable and quantitatively confirmed at a rapid rate in all samples.

  8. Ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of febuxostat in dog plasma and its application to a pharmacokinetic study.

    Science.gov (United States)

    Zhang, Tianhong; Sun, Yuanpeng; Zhang, Peng; Gao, Jingmei; Wang, Shanshan; He, Zhonggui

    2013-02-01

    A rapid, sensitive and selective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination of febuxostat in dog plasma. Using paclitaxel as an internal standard (IS), a simple liquid-liquid extraction method with ethyl acetate was adopted for plasma sample pretreatment. Separation was carried out on an Acquity UPLC BEH C(18) column with a mobile phase consisting of acetonitrile and water (containing 0.2% formic acid). The assay was linear in the concentration ranged from 5 to 5000 ng/mL with a lower limit of quantification of 5 ng/mL for febuxostat. The single run analysis was as short as 2.0 min. Finally, the developed method was successfully applied to the pharmacokinetic study of febuxostat tablets following oral administration at a single dose of 40 mg in beagle dogs. Copyright © 2012 John Wiley & Sons, Ltd.

  9. Development of a multiresidue method for the determination of endocrine disrupters in fish fillet using gas chromatography-triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Munaretto, Juliana S; Ferronato, Giovana; Ribeiro, Lucila C; Martins, Manoel L; Adaime, Martha B; Zanella, Renato

    2013-11-15

    Endocrine Disrupter Compounds (EDCs) are responsible for alterations in the endocrine system functions. Aquatic organisms are able to accumulate EDCs residues, being the major source of contamination for top predators and human consumers. This study aimed to develop and validate a method for the determination of 40 EDCs in fish fillet using modified QuEChERS and Gas Chromatography coupled with Mass Spectrometry in tandem (GC-MS/MS). A factorial design was used to optimize the extraction procedure. Method validation presented recoveries from 70.1% to 120.0% with RSDfish fillet from different species and residues of bisphenol A, chlorpyrifos and bifenthrin were detected. The proposed method proved to be effective for the determination of EDCs in fish fillet at very low concentration levels. © 2013 Elsevier B.V. All rights reserved.

  10. Simplified sample preparation method for protein identification by matrix-assisted laser desorption/ionization mass spectrometry: in-gel digestion on the probe surface

    DEFF Research Database (Denmark)

    Stensballe, A; Jensen, Ole Nørregaard

    2001-01-01

    /ionization-time of flight mass spectrometry (MALDI-TOF-MS) is used as the first protein screening method in many laboratories because of its inherent simplicity, mass accuracy, sensitivity and relatively high sample throughput. We present a simplified sample preparation method for MALDI-MS that enables in-gel digestion...... for protein identification similar to that obtained by the traditional protocols for in-gel digestion and MALDI peptide mass mapping of human proteins, i.e. approximately 60%. The overall performance of the novel on-probe digestion method is comparable with that of the standard in-gel sample preparation...... protocol while being less labour intensive and more cost-effective due to minimal consumption of reagents, enzymes and consumables. Preliminary data obtained on a MALDI quadrupole-TOF tandem mass spectrometer demonstrated the utility of the on-probe digestion protocol for peptide mass mapping and peptide...

  11. Mass spectrometry

    DEFF Research Database (Denmark)

    Nyvang Hartmeyer, Gitte; Jensen, Anne Kvistholm; Böcher, Sidsel

    2010-01-01

    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is currently being introduced for the rapid and accurate identification of bacteria. We describe 2 MALDI-TOF MS identification cases - 1 directly on spinal fluid and 1 on grown bacteria. Rapidly obtained...

  12. Sensitive method for the quantitative determination of proguanil and its metabolites in rat blood and plasma by liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Leveque, Nathalie L; Charman, William N; Chiu, Francis C K

    2006-01-18

    A sensitive, simple and fast liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 1-(4-chlorophenyl)biguanide (4CPB), was developed and validated over a concentration range of 1-2000 ng/mL using only 50 microL of blood or plasma. After a simple solvent precipitation procedure, the supernatant was analysed directly by HPLC-MS/MS. Separation was achieved using an ethyl-linked phenyl reverse phase column with polar endcapping with an acetonitrile-water-formic acid gradient. Mass spectrometry was performed using a triple quadrupole mass spectrometer operating in positive electrospray ionization mode. The elution of PG (254.07-->169.99), CG (252.12-->195.02) and 4CPB (212.06-->153.06) was monitored using selected reaction monitoring. The three compounds and the internal standard (chloroproguanil) were well separated by HPLC and no interfering peaks were detected at the usual concentrations found in blood and plasma. The limit of quantification of PG and CG was 1 ng/mL and 5 ng/mL for 4CPB in rat blood and plasma. The extraction efficiency of PG, CG and 4CPB from rat blood and plasma was higher than 73%. The intra- and inter-assay variability of PG, CG and 4CPB were within 12% and the accuracy within +/-5%. This new assay offers higher sensitivity and a much shorter run time over earlier methods.

  13. Determination of steroid hormones in a human-serum reference material by isotope dilution--mass spectrometry: A candidate definitive method for cortisol

    International Nuclear Information System (INIS)

    Patterson, D.G.; Patterson, M.B.; Culbreth, P.H.; Fast, D.M.; Holler, J.S.; Sampson, E.J.; Bayse, D.D.

    1984-01-01

    We report a method, based on isotope dilution--mass spectrometry, for determining cortisol in a pooled specimen of human serum. Isotopically labeled cortisol is added to 5.0 mL of serum so that the molar concentrations of labeled cortisol and unlabeled cortisol are approximately equal. The specimen and two calibration standards are extracted with dichloromethane, and the extracted cortisol is converted to the methoxime-trimethylsilyl ether derivative. Samples and standards are analyzed by gas chromatography--mass spectrometry by monitoring the peak areas for m/z 605 and 608. The cortisol concentration is calculated by linear interpolation between the two bracketing standards. Variances of data collected during six weeks showed that the overall coefficient of variation (CV) was 0.69% (n . 32); the within-vial CV, 0.63%; the among-vial CV, 0.22%; and the among-day CV, 0.15% (means . 3.973 nmol/vial). Method specificity was demonstrated by liquid chromatographic as well as C 8 mini-column cleanup of samples before derivation, by alternative ion monitoring at m/z 636 and 639, and by negative-ion chemical ionization at m/z 459 and 462. Derivatives of all observed degradation products of cortisol under basic, neutral, and acidic conditions did not interfere

  14. Rapid and accurate liquid chromatography and tandem mass spectrometry method for the simultaneous quantification of ten metabolic reactions catalyzed by hepatic cytochrome P450 enzymes.

    Science.gov (United States)

    Shi, Rong; Ma, Bingliang; Wu, Jiasheng; Wang, Tianming; Ma, Yueming

    2015-10-01

    The hepatic cytochrome P450 enzymes play a central role in the biotransformation of endogenous and exogenous substances. A sensitive high-throughput liquid chromatography with tandem mass spectrometry assay was developed and validated for the simultaneous quantification of the products of ten metabolic reactions catalyzed by hepatic cytochrome P450 enzymes. After the substrates were incubated separately, the samples were pooled and analyzed by liquid chromatography with tandem mass spectrometry using an electrospray ionization source in the positive and negative ion modes. The method exhibited linearity over a broad concentration range, insensitivity to matrix effects, and high accuracy, precision, and stability. The novel method was successfully applied to study the kinetics of phenacetin-O deethylation, coumarin-7 hydroxylation, bupropion hydroxylation, taxol-6 hydroxylation, omeprazole-5 hydroxylation, dextromethorphan-O demethylation, tolbutamide-4 hydroxylation, chlorzoxazone-6 hydroxylation, testosterone-6β hydroxylation, and midazolam-1 hydroxylation in rat liver microsomes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Multiclass method for the quantification of 92 veterinary antimicrobial drugs in livestock excreta, wastewater, and surface water by liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Gao, Jinfang; Cui, Yonghui; Tao, Yanfei; Huang, Lingli; Peng, Dapeng; Xie, Shuyu; Wang, Xu; Liu, Zhenli; Chen, Dongmei; Yuan, Zonghui

    2016-11-01

    A simple multiresidue method was developed for detecting and quantifying 92 veterinary antimicrobial drugs from eight classes (β-lactams, quinolones, sulfonamides, tetracyclines, lincomycins, macrolides, chloramphenicols, and pleuromutilin) in livestock excreta and water by liquid chromatography with tandem mass spectrometry. The feces samples were extracted by ultrasound-assisted extraction with a mixture of acetonitrile/water (80:20, v/v) and edetate disodium, followed by a cleanup using solid-phase extraction with an amino cartridge. Water samples were purified with hydrophilic-lipophilic balance solid-phase extraction column. Urine samples were extracted with acetonitrile and edetate disodium. Detection of veterinary antimicrobial drugs was achieved by liquid chromatography with tandem mass spectrometry using both positive and negative electrospray ionization mode. The recovery values of veterinary antimicrobial drugs in feces, urine, and water samples were 75-99, 85-110, and 85-101% and associated relative standard deviations were less than 15, 10, and 8%, respectively. The limits of quantification in feces, urine, and water samples were 0.5-1, 0.5-1, and 0.01-0.05 μg/L, respectively. This method was applied to determine real samples obtained from local farms and provides reliable quantification and identification results of 92 veterinary antimicrobial drugs in livestock excreta and water. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A comparative study of three tissue-cultured Dendrobium species and their wild correspondences by headspace gas chromatography-mass spectrometry combined with chemometric methods.

    Science.gov (United States)

    Chen, Nai-Dong; You, Tao; Li, Jun; Bai, Li-Tao; Hao, Jing-Wen; Xu, Xiao-Yuan

    2016-10-01

    Plant tissue culture technique is widely used in the conservation and utilization of rare and endangered medicinal plants and it is crucial for tissue culture stocks to obtain the ability to produce similar bioactive components as their wild correspondences. In this paper, a headspace gas chromatography-mass spectrometry method combined with chemometric methods was applied to analyze and evaluate the volatile compounds in tissue-cultured and wild Dendrobium huoshanense Cheng and Tang, Dendrobium officinale Kimura et Migo and Dendrobium moniliforme (Linn.) Sw. In total, 63 volatile compounds were separated, with 53 being identified from the three Dendrobium spp. Different provenances of Dendrobiums had characteristic chemicals and showed remarkable quantity discrepancy of common compositions. The similarity evaluation disclosed that the accumulation of volatile compounds in Dendrobium samples might be affected by their provenance. Principal component analysis showed that the first three components explained 85.9% of data variance, demonstrating a good discrimination between samples. Gas chromatography-mass spectrometry techniques, combined with chemometrics, might be an effective strategy for identifying the species and their provenance, especially in the assessment of tissue-cultured Dendrobium quality for use in raw herbal medicines. Copyright © 2016. Published by Elsevier B.V.

  17. Pressure-assisted electrokinetic injection for on-line enrichment in capillary electrophoresis-mass spectrometry: a sensitive method for measurement of ten haloacetic acids in drinking water.

    Science.gov (United States)

    Zhang, Huijuan; Zhu, Jiping; Aranda-Rodriguez, Rocio; Feng, Yong-Lai

    2011-11-07

    Haloacetic acids (HAAs) are by-products of the chlorination of drinking water containing natural organic matter and bromide. A simple and sensitive method has been developed for determination of ten HAAs in drinking water. The pressure-assisted electrokinetic injection (PAEKI), an on-line enrichment technique, was employed to introduce the sample into a capillary electrophoresis (CE)-electrospray ionization-tandem mass spectrometry system (ESI-MS/MS). HAAs were monitored in selected reaction monitoring mode. With 3 min of PAEKI time, the ten major HAAs (HAA10) in drinking water were enriched up to 20,000-fold into the capillary without compromising resolution. A simple solid phase clean-up method has been developed to eliminate the influence of ionic matrices from drinking water on PAEKI. Under conditions optimized for mass spectrometry, PAEKI and capillary electrophoresis, detection limits defined as three times ratio of signal to noise have been achieved in a range of 0.013-0.12 μg L(-1) for ten HAAs in water sample. The overall recoveries for all ten HAAs in drinking water samples were between 76 and 125%. Six HAAs including monochloro- (MCAA), dichloro- (DCAA), trichloro- (TCAA), monobromo- (MBAA), bromochloro- (BCAA), and bromodichloroacetic acids (BDCAA) were found in tap water samples collected. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  18. A candidate liquid chromatography mass spectrometry reference method for the quantification of the cardiac marker 1-32 B-type natriuretic peptide.

    Science.gov (United States)

    Torma, Attila F; Groves, Kate; Biesenbruch, Sabine; Mussell, Chris; Reid, Alan; Ellison, Steve; Cramer, Rainer; Quaglia, Milena

    2017-08-28

    B-type natriuretic peptide (BNP) is a 32 amino acid cardiac hormone routinely measured by immunoassays to diagnose heart failure. While it is reported that immunoassay results can vary up to 45%, no attempt of standardization and/or harmonization through the development of certified reference materials (CRMs) or reference measurement procedures (RMPs) has yet been carried out. B-type natriuretic peptide primary calibrator was quantified traceably to the International System of Units (SI) by both amino acid analysis and tryptic digestion. A method for the stabilization of BNP in plasma followed by protein precipitation, solid phase extraction (SPE) and liquid chromatography (LC) mass spectrometry (MS) was then developed and validated for the quantification of BNP at clinically relevant concentrations (15-150 fmol/g). The candidate reference method was applied to the quantification of BNP in a number of samples from the UK NEQAS Cardiac Markers Scheme to demonstrate its applicability to generate reference values and to preliminary evaluate the commutability of a potential CRM. The results from the reference method were consistently lower than the immunoassay results and discrepancy between the immunoassays was observed confirming previous data. The application of the liquid chromatography-mass spectrometry (LC-MS) method to the UK NEQAS samples and the correlation of the results with the immunoassay results shows the potential of the method to support external quality assessment schemes, to improve understanding of the bias of the assays and to establish RMPs for BNP measurements. Furthermore, the method has the potential to be multiplexed for monitoring circulating truncated forms of BNP.

  19. A column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry method to determine anandamide and 2-arachidonoylglycerol in plasma samples.

    Science.gov (United States)

    Marchioni, Camila; de Souza, Israel Donizeti; Grecco, Caroline Fernandes; Crippa, José Alexandre; Tumas, Vitor; Queiroz, Maria Eugênia Costa

    2017-05-01

    This study reports a fast, sensitive, and selective column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine the endocannabinoids (eCBs), anandamide (AEA), and 2-arachidonoylglycerol (2-AG) in plasma samples. This bidimensional system used a restricted access media column (RP-8 ADS, 25 mm × 4 mm × 25 μM) in the first dimension and a core-shell Kinetex C18 (100 mm × 2, 1.7 mm × 1 μM) column in the second dimension, followed by detection in a mass spectrometer triple quadrupole (multiple reactions monitoring mode) operating in the positive mode. RP-8 ADS was used for trace enrichment of eCBs (reverse phase partitioning) and macromolecular matrix size exclusion; the core-shell column was used for the chromatographic separation. The column switching UHPLC-MS/MS method presented a linear range spanning from 0.1 ng mL -1 (LOQ) to 6 ng mL -1 for AEA and from 0.04 ng mL -1 (LOQ) to 10 ng mL -1 for 2-AG. Excluding the LLOQ values, the precision assays provided coefficients of variation lower than 8% and accuracy with relative standard error values lower than 14%. Neither carryover nor matrix effects were detected. This high-throughput column switching method compared to conventional methods is time saving as it involves fewer steps, consumes less solvent, and presents lower LLOQ. The column switching UHPLC-MS/MS method was successfully applied to determine AEA and 2-AG in plasma samples obtained from Alzheimer's disease patients. Graphical abstract A column switching ultra high-performance liquid chromatography-tandem mass spectrometry method using RP-8 ADS column and core shell column to determine endocannabinoids in plasma samples.

  20. Liquid chromatography-tandem mass spectrometry method for the determination of thiosulfate in human blood and urine as an indicator of hydrogen sulfide poisoning.

    Science.gov (United States)

    Maseda, Chikatoshi; Hayakawa, Akira; Okuda, Katsuhiro; Asari, Masaru; Tanaka, Hiroki; Yamada, Hiromi; Jin, Shigeki; Horioka, Kie; Matoba, Kotaro; Shiono, Hiroshi; Matsubara, Kazuo; Shimizu, Keiko

    2017-01-01

    Being a stable metabolite of hydrogen sulfide, thiosulfate has been utilized as an index for hydrogen sulfide poisoning (HSP). Thiosulfate analysis is mainly performed using gas chromatography/mass spectrometry (GC-MS) due to its high sensitivity and specificity. The GC-MS analysis requires two-step derivatizations of thiosulfate, and the derivative is not stable in solution as it has a disulfide moiety. To resolve this stability issue, we developed a novel analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for monitoring the pentafluorobenzyl derivative of thiosulfate (the first reaction product of the GC-MS method) in this study. The established method exhibited high reproducibility despite being a more simplified and rapid procedure compare to the GC-MS method. Phenyl 4-hydroxybenzoate was used as an internal standard because 1,3,5-tribromobenzene which had been used in the GC-MS method was not suitable compound for LC-MS/MS with Electrospray ionization (ESI) negative detection. The linear regression of the peak area ratios versus concentrations was fitted over the concentration ranges of 0.5-250μM and 0.25-250μM in blood and urine, respectively. The validation results satisfied the acceptance criteria for intra- and inter-day accuracy and precision. Blood and urine samples from 12 suspected HSP cases were tested using this method. The thiosulfate concentration detected in the sample coincided well with that determined at the scene of each HSP accident. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. Application of radiochemical neutron activation and atomic absorption spectrometry methods for the study of nutrition-pollution interactions in children

    Energy Technology Data Exchange (ETDEWEB)

    Tran Bang Diep [Institute for Nuclear Science and Technique, VAEC, P.O. Box 5T-160, Hanoi (Viet Nam)]. E-mail: tranfbangdiepj@yahoo.com; Tran Dai Nghiep [Institute for Nuclear Science and Technique, VAEC, P.O. Box 5T-160, Hanoi (Viet Nam)]. E-mail: tdnghiep@vaec.gov.vn

    2005-07-01

    The application of radiochemical neutron activation analysis (RNAA) and atomic absorption spectrometry (AAS) is expected to aid in understanding and evaluating the effects of environmental pollution on the nutritional status of children already exposed to marginal malnutrition. Samples of placenta, of low-weight and control newborns groups, were collected for determination of nutritional elements and pollutants. The mean ratios of pollutants and nutrients such as Cd/Zn, Hg/Se and Pb/Ca were evaluated for both groups. All these ratios in the placenta of the low-weight newborns are higher than that of the healthy group. The degree of the nutrient-pollutant interaction is evaluated by quantity R, with mercury considered as the most active pollutant while calcium the most active nutrient among the involved elements in process of the interaction. (author)

  2. Application of radiochemical neutron activation and atomic absorption spectrometry methods for the study of nutrition-pollution interactions in children

    International Nuclear Information System (INIS)

    Tran Bang Diep; Tran Dai Nghiep

    2005-01-01

    The application of radiochemical neutron activation analysis (RNAA) and atomic absorption spectrometry (AAS) is expected to aid in understanding and evaluating the effects of environmental pollution on the nutritional status of children already exposed to marginal malnutrition. Samples of placenta, of low-weight and control newborns groups, were collected for determination of nutritional elements and pollutants. The mean ratios of pollutants and nutrients such as Cd/Zn, Hg/Se and Pb/Ca were evaluated for both groups. All these ratios in the placenta of the low-weight newborns are higher than that of the healthy group. The degree of the nutrient-pollutant interaction is evaluated by quantity R, with mercury considered as the most active pollutant while calcium the most active nutrient among the involved elements in process of the interaction. (author)

  3. Determination of radium activity in some natural mineral waters using radioactive chemical extraction method and alpha spectrometry

    International Nuclear Information System (INIS)

    Nguyen Thi Oanh; Duong Van Thang; Duong Duc Thang; Nguyen Van Khanh; Doan Thuy Hau; Pham Bao Ngoc

    2017-01-01

    The 226 Ra activity concentration in several of mineral water samples of Northern Vietnam was measured by using alpha spectrometry. Ra adsorption techniques on manganese oxide were applied to produce thin alpha samples. The efficiency of sample preparation process was determined by conducting similar procedures for IAEA reference materials. The 226 Ra content in mineral water ranged from (11.33 ± 1.00) mBq/l to (38.00 ± 4.50) mBq/l. The measured maximum values do not exceed the permissible limit radiation dose for all samples (100 mBq/l - USEPA ). This study may be useful for assessing impacts of radiation dose from mineral water on human health. (author)

  4. IR IMAGING AND VIBRATORY METHODS OF CONTROL AND DIAGNOSTICS OF THE EQUIPMENT AT OJSC «BSW – MANAGEMENT COMPANY OF HOLDING «BMC»

    Directory of Open Access Journals (Sweden)

    A. S. Shinkarev

    2017-01-01

    Full Text Available The article discusses the main methods of diagnostics of the equipment of OJSC «BSW – management company of holding «BMC». Presents results of diagnostics of various equipment with the description of the devices directly used for the diagnostic that can detect various defects of the equipment at the stage of their origination. Describes the advantages of these methods compared to other methods of control and diagnostics.

  5. The IRS-1 signaling system.

    Science.gov (United States)

    Myers, M G; Sun, X J; White, M F

    1994-07-01

    Insulin-receptor substrate 1 (IRS-1) is a principal substrate of the receptor tyrosine kinase for insulin and insulin-like growth factor 1, and a substrate for a tyrosine kinase activated by interleukin 4. IRS-1 undergoes multisite tyrosine phosphorylation and mediates downstream signals by 'docking' various proteins that contain Src homology 2 domains. IRS-1 appears to be a unique molecule; however, 4PS, a protein found mainly in hemopoietic cells, may represent another member of this family.

  6. A comprehensive high-resolution mass spectrometry approach for characterization of metabolites by combination of ambient ionization, chromatography and imaging methods.

    Science.gov (United States)

    Berisha, Arton; Dold, Sebastian; Guenther, Sabine; Desbenoit, Nicolas; Takats, Zoltan; Spengler, Bernhard; Römpp, Andreas

    2014-08-30

    An ideal method for bioanalytical applications would deliver spatially resolved quantitative information in real time and without sample preparation. In reality these requirements can typically not be met by a single analytical technique. Therefore, we combine different mass spectrometry approaches: chromatographic separation, ambient ionization and imaging techniques, in order to obtain comprehensive information about metabolites in complex biological samples. Samples were analyzed by laser desorption followed by electrospray ionization (LD-ESI) as an ambient ionization technique, by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging for spatial distribution analysis and by high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) for quantitation and validation of compound identification. All MS data were acquired with high mass resolution and accurate mass (using orbital trapping and ion cyclotron resonance mass spectrometers). Grape berries were analyzed and evaluated in detail, whereas wheat seeds and mouse brain tissue were analyzed in proof-of-concept experiments. In situ measurements by LD-ESI without any sample preparation allowed for fast screening of plant metabolites on the grape surface. MALDI imaging of grape cross sections at 20 µm pixel size revealed the detailed distribution of metabolites which were in accordance with their biological function. HPLC/ESI-MS was used to quantify 13 anthocyanin species as well as to separate and identify isomeric compounds. A total of 41 metabolites (amino acids, carbohydrates, anthocyanins) were identified with all three approaches. Mass accuracy for all MS measurements was better than 2 ppm (root mean square error). The combined approach provides fast screening capabilities, spatial distribution information and the possibility to quantify metabolites. Accurate mass measurements proved to be critical in order to reliably combine data from different MS

  7. Ionic liquid ultrasound assisted dispersive liquid-liquid microextraction method for preconcentration of trace amounts of rhodium prior to flame atomic absorption spectrometry determination

    Energy Technology Data Exchange (ETDEWEB)

    Molaakbari, Elaheh [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Young Research Society, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Mostafavi, Ali, E-mail: mostafavi.ali@gmail.com [Chemistry Department, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Afzali, Daryoush [Environment and Nanochemistry Department, Research Institute of Environmental Science, International Center for Science, High Technology and Environmental Science, Kerman (Iran, Islamic Republic of); Mineral Industries Research Center, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of)

    2011-01-30

    In this article, we consider ionic liquid based ultrasound-assisted dispersive liquid-liquid microextraction of trace amounts of rhodium from aqueous samples and show that this is a fast and reliable sample pre-treatment for the determination of rhodium ions by flame atomic absorption spectrometry. The Rh(III) was transferred into its complex with 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol as a chelating agent, and an ultrasonic bath with the ionic liquid, 1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide at room temperature was used to extract the analyte. The centrifuged rhodium complex was then enriched in the form of ionic liquid droplets and prior to its analysis by flame atomic absorption spectrometry, 300 {mu}L ethanol was added to the ionic liquid-rich phase. Finally, the influence of various parameters on the recovery of Rh(III) was optimized. Under optimum conditions, the calibration graph was linear in the range of 4.0-500.0 ng mL{sup -1}, the detection limit was 0.37 ng mL{sup -1} (3S{sub b}/m, n = 7) and the relative standard deviation was {+-}1.63% (n = 7, C = 200 ng mL{sup -1}). The results show that ionic liquid based ultrasound assisted dispersive liquid-liquid microextraction, combined with flame atomic absorption spectrometry, is a rapid, simple, sensitive and efficient analytical method for the separation and determination of trace amounts of Rh(III) ions with minimum organic solvent consumption.

  8. Evaluation of a simple protein extraction method for species identification of clinically relevant staphylococci by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Matsuda, Naoto; Matsuda, Mari; Notake, Shigeyuki; Yokokawa, Hirohide; Kawamura, Yoshiaki; Hiramatsu, Keiichi; Kikuchi, Ken

    2012-12-01

    In clinical microbiology, bacterial identification is labor-intensive and time-consuming. A solution for this problem is the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). In this study, we evaluated a modified protein extraction method of identification performed on target plates (on-plate extraction method) with MALDI-TOF (Bruker Microflex LT with Biotyper version 3.0) and compared it to 2 previously described methods: the direct colony method and a standard protein extraction method (standard extraction method). We evaluated the species of 273 clinical strains and 14 reference strains of staphylococci. All isolates were characterized using the superoxide dismutase A sequence as a reference. For the species identification, the on-plate, standard extraction, and direct colony methods identified 257 isolates (89.5%), 232 isolates (80.8%), and 173 isolates (60.2%), respectively, with statistically significant differences among the three methods (P extraction method is at least as good as standard extraction in identification rate and has the advantage of a shorter processing time.

  9. Quantification of imatinib in human serum: validation of a high-performance liquid chromatography-mass spectrometry method for therapeutic drug monitoring and pharmacokinetic assays

    Directory of Open Access Journals (Sweden)

    Rezende VM

    2013-08-01

    Full Text Available Vinicius Marcondes Rezende,1 Ariane Rivellis,1 Mafalda Megumi Yoshinaga Novaes,1 Dalton de Alencar Fisher Chamone,2 Israel Bendit1,21Laboratory of Tumor Biology, 2Department of Hematology, School of Medicine, University of São Paulo, São Paulo, BrazilBackground: Imatinib mesylate has been a breakthrough treatment for chronic myeloid leukemia. It has become the ideal tyrosine kinase inhibitor and the standard treatment for chronic-phase leukemia. Striking results have recently been reported, but intolerance to imatinib and noncompliance with treatment remain to be solved. Molecular monitoring by quantitative real-time polymerase chain reaction is the gold standard for monitoring patients, and imatinib blood levels have also become an important tool for monitoring.Methods: A fast and cheap method was developed and validated using high-performance liquid chromatography-mass spectrometry for quantification of imatinib in human serum and tamsulosin as the internal standard. Remarkable advantages of the method includes use of serum instead of plasma, less time spent on processing and analysis, simpler procedures, and requiring reduced amounts of biological material, solvents, and reagents. Stability of the analyte was also studied. This research also intended to drive the validation scheme in clinical centers. The method was validated according to the requirements of the US Food and Drug Administration and Brazilian National Health Surveillance Agency within the range of 0.500–10.0 µg/mL with a limit of detection of 0.155 µg/mL. Stability data for the analyte are also presented.Conclusion: Given that the validated method has proved to be linear, accurate, precise, and robust, it is suitable for pharmacokinetic assays, such as bioavailability and bioequivalence, and is being successfully applied in routine therapeutic drug monitoring in the hospital service.Keywords: imatinib, high-performance liquid chromatography-mass spectrometry, therapeutic

  10. Rapid method for direct identification of bacteria in urine and blood culture samples by matrix-assisted laser desorption ionization time-of-flight mass spectrometry: intact cell vs. extraction method.

    Science.gov (United States)

    Ferreira, L; Sánchez-Juanes, F; Muñoz-Bellido, J L; González-Buitrago, J M

    2011-07-01

    Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a fast and reliable technology for the identification of microorganisms with proteomics approaches. Here, we compare an intact cell method and a protein extraction method before application on the MALDI plate for the direct identification of microorganisms in both urine and blood culture samples from clinical microbiology laboratories. The results show that the intact cell method provides excellent results for urine and is a good initial method for blood cultures. The extraction method complements the intact cell method, improving microorganism identification from blood culture. Thus, we consider that MALDI-TOF MS performed directly on urine and blood culture samples, with the protocols that we propose, is a suitable technique for microorganism identification, as compared with the routine methods used in the clinical microbiology laboratory. © 2010 The Authors. Clinical Microbiology and Infection © 2010 European Society of Clinical Microbiology and Infectious Diseases.

  11. Inhibition of PTP1B Restores IRS1-Mediated Hepatic Insulin Signaling in IRS2-Deficient Mice

    Science.gov (United States)

    González-Rodríguez, Águeda; Gutierrez, Jose A. Mas; Sanz-González, Silvia; Ros, Manuel; Burks, Deborah J.; Valverde, Ángela M.

    2010-01-01

    OBJECTIVE Mice with complete deletion of insulin receptor substrate 2 (IRS2) develop hyperglycemia, impaired hepatic insulin signaling, and elevated gluconeogenesis, whereas mice deficient for protein tyrosine phosphatase (PTP)1B display an opposing hepatic phenotype characterized by increased sensitivity to insulin. To define the relationship between these two signaling pathways in the regulation of liver metabolism, we used genetic and pharmacological approaches to study the effects of inhibiting PTP1B on hepatic insulin signaling and expression of gluconeogenic enzymes in IRS2−/− mice. RESEARCH DESIGN AND METHODS We analyzed glucose homeostasis and insulin signaling in liver and isolated hepatocytes from IRS2−/− and IRS2−/−/PTP1B−/− mice. Additionally, hepatic insulin signaling was assessed in control and IRS2−/− mice treated with resveratrol, an antioxidant present in red wine. RESULTS In livers of hyperglycemic IRS2−/− mice, the expression levels of PTP1B and its association with the insulin receptor (IR) were increased. The absence of PTP1B in the double-mutant mice restored hepatic IRS1-mediated phosphatidylinositol (PI) 3-kinase/Akt/Foxo1 signaling. Moreover, resveratrol treatment of hyperglycemic IRS2−/− mice decreased hepatic PTP1B mRNA and inhibited PTP1B activity, thereby restoring IRS1-mediated PI 3-kinase/Akt/Foxo1 signaling and peripheral insulin sensitivity. CONCLUSIONS By regulating the phosphorylation state of IR, PTB1B determines sensitivity to insulin in liver and exerts a unique role in the interplay between IRS1 and IRS2 in the modulation of hepatic insulin action. PMID:20028942

  12. Development and validation of a method for detection and quantification of ochratoxin A in green coffee using liquid chromatography coupled to mass spectrometry

    Directory of Open Access Journals (Sweden)

    Raquel Duarte da Costa Cunha Bandeira

    2012-12-01

    Full Text Available A method using Liquid Chromatography Tanden Mass Spectrometry (LC-MS/MS with matrix-matched calibration curve was developed and validated for determining ochratoxin A (OTA in green coffee. Linearity was found between 3.0 and 23.0 ng.g-1. Mean recoveries ranged between 90.45% and 108.81%; the relative standard deviation under repeatability and intermediate precision conditions ranged from 5.39% to 9.94% and from 2.20% to 14.34%, respectively. The limits of detection and quantification were 1.2 ng.g-1 and 3.0 ng.g-¹, respectively. The method developed was suitable and contributed to the field of mycotoxin analysis, and it will be used for future production of the Certified Reference Material (CRM for OTA in coffee.

  13. Novel Selectivity-Based Forensic Toxicological Validation of a Paper Spray Mass Spectrometry Method for the Quantitative Determination of Eight Amphetamines in Whole Blood

    Science.gov (United States)

    Teunissen, Sebastiaan F.; Fedick, Patrick W.; Berendsen, Bjorn J. A.; Nielen, Michel W. F.; Eberlin, Marcos N.; Graham Cooks, R.; van Asten, Arian C.

    2017-12-01

    Paper spray tandem mass spectrometry is used to identify and quantify eight individual amphetamines in whole blood in 1.3 min. The method has been optimized and fully validated according to forensic toxicology guidelines, for the quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy- N-methylamphetamine (MDMA), 3,4-methylenedioxy- N-ethylamphetamine (MDEA), para-methoxyamphetamine (PMA), para-methoxymethamphetamine (PMMA), and 4-fluoroamphetamine (4-FA). Additionally, a new concept of intrinsic and application-based selectivity is discussed, featuring increased confidence in the power to discriminate the amphetamines from other chemically similar compounds when applying an ambient mass spectrometric method without chromatographic separation. Accuracy was within ±15% and average precision was better than 15%, and better than 20% at the LLOQ. Detection limits between 15 and 50 ng/mL were obtained using only 12 μL of whole blood. [Figure not available: see fulltext.

  14. Method development for the analysis of 1,4-dioxane in drinking water using solid-phase extraction and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Grimmett, Paul E; Munch, Jean W

    2009-01-01

    1,4-Dioxane has been identified as a probable human carcinogen and an emerging contaminant in drinking water. The United States Environmental Protection Agency's (U.S. EPA) National Exposure Research Laboratory (NERL) has developed a method for the analysis of 1,4-dioxane in drinking water at ng/L concentrations. The method consists of an activated carbon solid-phase extraction of 500-mL or 100-mL water samples using dichloromethane as the elution solvent. The extracts are analyzed by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. In the NERL laboratory, recovery of 1,4-dioxane ranged from 94-110% in fortified laboratory reagent water and recoveries of 96-102% were demonstrated for fortified drinking water samples. The relative standard deviations for replicate analyses were less than 6% at concentrations exceeding the minimum reporting level.

  15. Validation of a method for simultaneous determination of nitroimidazoles, benzimidazoles and chloramphenicols in swine tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Xia, Xi; Wang, Yuanyuan; Wang, Xia; Li, Yun; Zhong, Feng; Li, Xiaowei; Huang, Yaoling; Ding, Shuangyang; Shen, Jianzhong

    2013-05-31

    This paper presents a sensitive and confirmatory multi-residue method for the analysis of 23 veterinary drugs and metabolites belonging to three classes (nitroimidazoles, benzimidazoles, and chloramphenicols) in porcine muscle, liver, and kidney. After extracted with ethyl acetate and basic ethyl acetate sequentially, the crude extracts were defatted with hexane and further purified using Oasis MCX solid-phase extraction cartridges. Rapid determination was carried out by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Data acquisition was performed under positive and negative mode simultaneously. Recoveries based on matrix-matched calibrations for meat, liver, and kidney ranged from 50.6 to 108.1%. The method quantification limits were in the range of 3-100ng/kg. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. A rapid monitoring method for inorganic arsenic in rice flour using reversed phase-high performance liquid chromatography-inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Narukawa, Tomohiro; Chiba, Koichi; Sinaviwat, Savarin; Feldmann, Jörg

    2017-01-06

    A new rapid monitoring method by means of high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) following the heat-assisted extraction was developed for measurement of total inorganic arsenic species in rice flour. As(III) and As(V) eluted at the same retention time and completely separated from organoarsenic species by an isocratic elution program on a reversed phase column. Therefore, neither ambiguous oxidation of arsenite to arsenate nor the integration of two peaks were necessary to determine directly the target analyte inorganic arsenic. Rapid injection allowed measuring 3 replicates within 6min and this combined with a quantitative extraction of all arsenic species from rice flour by a 15min HNO 3 -H 2 O 2 extraction makes this the fastest laboratory based method for inorganic arsenic in rice flour. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. HOMA1-IR and HOMA2-IR indexes in identifying insulin resistance and metabolic syndrome - Brazilian Metabolic Syndrome Study (BRAMS)

    OpenAIRE

    Geloneze, B; Vasques, ACJ; Stabe, CFC; Pareja, JC; Rosado, LEFPD; de Queiroz, EC; Tambascia, MA

    2009-01-01

    Objective: To investigate cut-off values for HOMA1-IR and HOMA2-IR to identify insulin resistance (IR) and metabolic syndrome (MS), and to assess the association of the indexes with components of the MS. Methods: Nondiabetic subjects from the Brazilian Metabolic Syndrome Study were studied (n = 1,203, 18 to 78 years). The cut-off values for IR were determined from the 9011 percentile in the healthy group (n = 297) and, for MS, a ROC curve was generated for the total sample. Results: In the he...

  18. Comparison of conventional liquid chromatography-tandem mass spectrometry versus microflow liquid chromatography-tandem mass spectrometry within the framework of full method validation for simultaneous quantification of 40 antidepressants and neuroleptics in whole blood.

    Science.gov (United States)

    Steuer, Andrea E; Poetzsch, Michael; Koenig, Magdalena; Tingelhoff, Eva; Staeheli, Sandra N; Roemmelt, Andreas T; Kraemer, Thomas

    2015-02-13

    Microflow liquid chromatography (MFLC) coupled to mass spectrometry (MS) is claimed to improve analysis throughput, reduce matrix effects and lower mobile phase consumption. This statement was checked within the framework of method validation of a multi-analyte procedure in clinical and forensic toxicology employing MFLC-MS/MS and conventional LC-MS/MS. 200 μL whole blood were spiked with 50 μL internal standard mixture and extracted by protein precipitation. The concentrated extract was separated into two vials. One was analyzed using a Thermo Fisher Ultimate liquid chromatography system coupled to an ABSciex 5500 QTrap mass spectrometer (LC-MS/MS) and one by an ABSciex Eksigent Microflow LC system coupled to an ABSciex 4500 linear ion trap quadrupole MS (MFLC-MS/MS). Both methods were fully validated and compared in terms of selectivity, stability, limits, calibration model, recovery (RE), matrix effects (ME), bias, imprecision and beta tolerance interval for 40 antidepressants and neuroleptics including 9 metabolites. Both methods had comparable LODs, LOQs and calibration models with some exceptions. The MFLC system showed slightly higher coefficients of variation (CVs) in the RE experiments. ME were reproducible in both systems but with lower CVs in the conventional LC system. Acceptance criteria for imprecision and bias were fulfilled for 32 analytes on the LC and for 28 analytes on the MFLC system. Beta tolerance intervals indicated better reproducibility in terms of narrower intervals for the conventional LC system. The advantages of the MFLC system were low mobile phase consumption, short run time, and better peak separation. The systems were comparable in terms of peak interference, LOD, ME, bias and imprecision. The advantages of the conventional LC system were more data points per peak, linear calibration models, stable retention times and better beta tolerance intervals. Due to higher robustness, the conventional LC system was finally chosen for

  19. Study of two new methods of geochronometry: dating method of carbonaceous formations by U-series disequilibrium gamma spectrometry; ESR dating method of rich U-content fossil dental enamel

    International Nuclear Information System (INIS)

    Ma, Jean-Luc

    1984-01-01

    First, the U-series disequilibrium dating method was re-examined using non-destructive γ-spectrometry. A new low-background (≤ 10 ppb U- equivalent) Ge-HP γ-spectrometer has been used to date travertine with small U-content (∼ 0.1 ppm) and low (≤ 5%) Th/U , content, by comparison with old-limestone γ-spectra. Second, a new ESR dating method has been developed using fossil dental enamel which is rich in U-content (10 - 100 ppm). Both methods were applied to Arago Cave (Tautavel, France): - with an ionium-age of 120 ka (10%), the upper travertine seems to have been set up during the Riss-deglaciation period. - the high (∼ 50%) Th/U-content samples of the intermediate travertine are un-datable. - the ESR-age of EQUUS mosbachensis enamel is 400 ka (10%) for the G-soil of Arago. XXI H. erectus, and 600 ka (10%) for the Q-soil above (- 1 m) of the lower travertine of which Io-age is older than 350 ka. (author)

  20. A simple and fast method for assessment of the nitrogen–phosphorus–potassium rating of fertilizers using high-resolution continuum source atomic and molecular absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bechlin, Marcos André; Fortunato, Felipe Manfroi; Moutinho da Silva, Ricardo; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta, E-mail: anchieta@iq.unesp.br

    2014-11-01

    The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular absorption spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620 nm, respectively, and K using the wing of the alternative line at 404.722 nm allowed calibration curves to be constructed in the ranges 500–5000 mg L{sup −1} N (r = 0.9994), 100–2000 mg L{sup −1} P (r = 0.9946), and 100–2500 mg L{sup −1} K (r = 0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97–105% (NO{sub 3}{sup −}-N), 95–103% (NH{sub 4}{sup +}-N), 93–103% (urea-N), 99–108% (P), and 99–102% (K). The relative standard deviations (n = 12) for N, P, and K were 6, 4, and 2%, respectively. - Highlights: • A single technique is proposed to analyze NPK fertilizer. • HR-CS FAAS is proposed for the first time for N, P and K determination in fertilizers. • The method employs the same sample preparation and dilution for the three analytes. • Addition of H{sub 2}O{sub 2} allows analysis of fertilizers with different nitrogen species. • Proposal provides advantages over traditional methods in terms of cost and time.

  1. Development of a new ultra-high performance liquid chromatography - tandem mass spectrometry method for determination of ambroxol hydrochloride in serum with pharmacokinetic application

    Directory of Open Access Journals (Sweden)

    Vujović Maja M.

    2016-01-01

    Full Text Available Ambroxol hydrochloride is an expectorant agent, successfully applied in mucolytic therapy for acute and chronic bronchopulmonary diseases. The drug regulates not only mucus secretion but also showed antioxidant, anti-inflammatory and local anesthetic properties. To supplement the pharmacokinetic and toxicological studies of ambroxol, a rapid ultra-high performance liquid chromatography-tandem mass spectrometry method for the quantitation of ambroxol in rabbit serum was developed. A validation of the method was performed as per the ICH guidelines for the validation of bioanalytical methods. The chromatographic separation was achieved in a submicron Kinetex RP - C18 - column (2.1 mm x 50 mm, 1.3μm using the no buffer mobile phase. The ESI mass spectrometry in the MRM mode was used with a typical transitions m/z 378.9→263.8 for ambroxol and m/z 455.2→165.0 for IS. Linearity was determined with an average coefficient of determination >0.999 over the dynamic range from 0.5 - 200 ng/mL with LOD and LOQ of 0.25 ng/mL and 0.5 ng/mL, respectively. The results of the intra- and inter-day precision and accuracy determined in different days were all found to be within the acceptable limits ±15%. The present method was successfully applied to pharmacokinetic study in the rabbits after a single oral dose administration. [Projekat Ministarstva nauke Republike Srbije, br. 175045

  2. A simple and fast method for assessment of the nitrogen–phosphorus–potassium rating of fertilizers using high-resolution continuum source atomic and molecular absorption spectrometry

    International Nuclear Information System (INIS)

    Bechlin, Marcos André; Fortunato, Felipe Manfroi; Moutinho da Silva, Ricardo; Ferreira, Edilene Cristina; Gomes Neto, José Anchieta

    2014-01-01

    The determination of N, P, and K in fertilizers by high-resolution continuum source flame atomic and molecular absorption spectrometry is proposed. Under optimized conditions, measurements of the diatomic molecules NO and PO at 215.360 and 247.620 nm, respectively, and K using the wing of the alternative line at 404.722 nm allowed calibration curves to be constructed in the ranges 500–5000 mg L −1 N (r = 0.9994), 100–2000 mg L −1 P (r = 0.9946), and 100–2500 mg L −1 K (r = 0.9995). Commercial fertilizers were analyzed by the proposed method and the concentrations of N, P, and K were found to be in agreement with those obtained by Kjeldahl, spectrophotometric, and flame atomic emission spectrometry methods, respectively, at a 95% confidence level (paired t-test). A phosphate rock certified reference material (CRM) was analyzed and the results for P and K were in agreement with the reference values. Recoveries from spiked CRM were in the ranges 97–105% (NO 3 − -N), 95–103% (NH 4 + -N), 93–103% (urea-N), 99–108% (P), and 99–102% (K). The relative standard deviations (n = 12) for N, P, and K were 6, 4, and 2%, respectively. - Highlights: • A single technique is proposed to analyze NPK fertilizer. • HR-CS FAAS is proposed for the first time for N, P and K determination in fertilizers. • The method employs the same sample preparation and dilution for the three analytes. • Addition of H 2 O 2 allows analysis of fertilizers with different nitrogen species. • Proposal provides advantages over traditional methods in terms of cost and time

  3. Performance assessment of two lysis methods for direct identification of yeasts from clinical blood cultures using MALDI-TOF mass spectrometry.

    Science.gov (United States)

    Jeddi, Fakhri; Yapo-Kouadio, Gisèle Cha; Normand, Anne-Cécile; Cassagne, Carole; Marty, Pierre; Piarroux, Renaud

    2017-02-01

    In cases of fungal infection of the bloodstream, rapid species identification is crucial to provide adapted therapy and thereby ameliorate patient outcome. Currently, the commercial Sepsityper kit and the sodium-dodecyl sulfate (SDS) method coupled with MALDI-TOF mass spectrometry are the most commonly reported lysis protocols for direct identification of fungi from positive blood culture vials. However, the performance of these two protocols has never been compared on clinical samples. Accordingly, we performed a two-step survey on two distinct panels of clinical positive blood culture vials to identify the most efficient protocol, establish an appropriate log score (LS) cut-off, and validate the best method. We first compared the performance of the Sepsityper and the SDS protocols on 71 clinical samples. For 69 monomicrobial samples, mass spectrometry LS values were significantly higher with the SDS protocol than with the Sepsityper method (P < .0001), especially when the best score of four deposited spots was considered. Next, we established the LS cut-off for accurate identification at 1.7, based on specimen DNA sequence data. Using this LS cut-off, 66 (95.6%) and 46 (66.6%) isolates were correctly identified at the species level with the SDS and the Sepsityper protocols, respectively. In the second arm of the survey, we validated the SDS protocol on an additional panel of 94 clinical samples. Ninety-two (98.9%) of 93 monomicrobial samples were correctly identified at the species level (median LS = 2.061). Overall, our data suggest that the SDS method yields more accurate species identification of yeasts, than the Sepsityper protocol. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. A new Density Functional Theory (DFT) based method for supporting the assignment of vibrational signatures of mannan and cellulose—Analysis of palm kernel cake hydrolysis by ATR-FT-IR spectroscopy as a case study

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Sanadi, Anand Ramesh; Jørgensen, Henning

    2011-01-01

    Attenuated Total Reflectance (ATR) FT-IR spectroscopy gives in situ information on molecular concentration, organization and interactions in plant cell walls. We demonstrate its potential for further developments by a case study which combines ATR-FT-IR spectroscopy with a recently published DFT...... a decreasing degree of polymerization to be a plausible cause, although others may interfere. Keywords: Cellulose; Mannan; FT-IR; DFT; Molecular modelling; Palm kernel...

  5. Fibre-Optic IR-Spectroscopy for Biomedical Diagnostics

    OpenAIRE

    Bindig, Uwe; Gersonde, Ingo; Meinke, Martina; Becker, Yukiyo; Müller, Gerhard

    2003-01-01

    The use of microscopy is a valuable means of gaining vital information for medical diagnostics. Due to a number of recent technological developments advances have been made in IR microscopy and in particular, rapid detection methods. Microscopic examination methods usually involve sampling followed by a method of sample purification or preparation. The advantages of the IR analytical method are that it is based on a direct, non‒destructive measurement of sample material and that the resulting...

  6. A simple method for rapid microbial identification from positive monomicrobial blood culture bottles through matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

    Science.gov (United States)

    Lin, Jung-Fu; Ge, Mao-Cheng; Liu, Tsui-Ping; Chang, Shih-Cheng; Lu, Jang-Jih

    2017-06-30

    Rapid identification of microbes in the bloodstream is crucial in managing septicemia because of its high disease severity, and direct identification from positive blood culture bottles through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) can shorten the turnaround time. Therefore, we developed a simple method for rapid microbiological identification from positive blood cultures by using MALDI-TOF MS. We modified previously developed methods to propose a faster, simpler and more economical method, which includes centrifugation and hemolysis. Specifically, our method comprises two-stage centrifugation with gravitational acceleration (g) at 600g and 3000g, followed by the addition of a lysis buffer and another 3000g centrifugation. In total, 324 monomicrobial bacterial cultures were identified. The success rate of species identification was 81.8%, which is comparable with other complex methods. The identification success rate was the highest for Gram-negative aerobes (85%), followed by Gram-positive aerobes (78.2%) and anaerobes (67%). The proposed method requires less than 10 min, costs less than US$0.2 per usage, and facilitates batch processing. We conclude that this method is feasible for clinical use in microbiology laboratories, and can serve as a reference for treatments or further complementary diagnostic testing. Copyright © 2017. Published by Elsevier B.V.

  7. COINTOF mass spectrometry: design of a time-of-flight analyzer and development of the analysis method

    International Nuclear Information System (INIS)

    Teyssier, C.

    2012-01-01

    DIAM (Device for the irradiation of molecular clusters) is a newly designed experimental setup to investigate processes resulting from the irradiation of molecular nano-systems by 20-150 keV protons. One of its specificities relies on the original technique of mass spectrometry named COINTOF (Correlated Ion and Neutral Time Of Flight) consisting in correlated measurements of the time of flight of charged and neutral fragments produced by the dissociation of a single molecular ion parent. A strategy of treatment and analysis of the detection signals was developed to distinguish two fragments close in time ( 3 O + and two water molecules. The distribution of the time of flight difference between the two neutral fragments is measured providing an estimate of the kinetic energy release of a few eV. In parallel, a second time-of-flight mass spectrometer was designed. It associates a linear time-of-flight and an orthogonal time-of-flight and integrates position detectors (delay line anode). Simulations demonstrate the potentials of the new analyzer. Finally, research works were led at the laboratory R.-J. A. Levesque (Universite de Montreal) on the imaging capabilities of the multi-pixel detectors of the MPX-ATLAS collaboration. (author)

  8. Multianalyte, high-throughput liquid chromatography tandem mass spectrometry method for the sensitive determination of fungicides and insecticides in wine.

    Science.gov (United States)

    Castro, Gabriela; Pérez-Mayán, Leticia; Rodríguez-Cabo, Tamara; Rodríguez, Isaac; Ramil, Maria; Cela, Rafael

    2018-01-01

    Evidence of pesticide transfer from grapes to wine, added to differences in the national regulations regarding the number and the maximum concentration of these species in wine, demands analytical procedures suitable for their routine control in this foodstuff. In this research, solid-phase extraction (SPE) and ultra-performance liquid chromatography (UPLC), with tandem mass spectrometry (MS/MS) detection, are combined to obtain a sensitive and rapid procedure to determine 50 pesticides in red and white wines. Efficiency and selectivity of sample preparation are correlated with the type of sorbent, the elution solvent, and the physicochemical properties of pesticides. SPE of 2-mL wine samples followed by direct injection of the extract in the UPLC-MS/MS system provides quantification limits (LOQs) below 1 ng mL -1 for 48 out of 50 compounds, linear responses up to 200 ng mL -1 , and acceptable accuracy, employing quantification against solvent-based standards, for 45 species. A total analysis time of 10 min, including compounds separation and re-equilibration of the UPLC column, was achieved. The developed methodology was applied to 25 wines (20 conventional and 5 ecological), produced in 7 different countries. Out of 27 pesticides quantified in these wines, 12 displayed occurrence frequencies above 24%; moreover, all wines, except one of the ecological ones, contained residues from at least one pesticide.

  9. Analytical methods for proteome data obtained from SDS-PAGE multi-dimensional separation and mass spectrometry

    Directory of Open Access Journals (Sweden)

    Gun Wook Park

    2010-03-01

    Full Text Available For proteome analysis, various experimental protocols using mass spectrometry have been developed over thelast decade. The different protocols have differing performances and degrees of accuracy. Furthermore, the “best”protocol for a proteomic analysis of a sample depends on the purpose of the analysis, especially in connection withdisease proteomics, including biomarker discovery and therapeutics analyses of human serum or plasma. Theprotein complexity and the wide dynamic range of blood samples require high-dimensional separation technology.In this article, we review proteome analysis protocols in which both Sodium Dodecyl Sulfate-Polyacryl Amide GelElectrophoresis(SDS-PAGE and liquid chromatography are used for peptide and protein separations. Multidimensionalseparation technology supplies a high-quality dataset of tandem mass spectra and reveals signals fromlow-abundance proteins, although it can be time-consuming and laborious work. We survey shotgun proteomicsprotocols using SDS-PAGE and liquid chromatography and introduce bioinformatics tools for the analysis ofproteomics data. We also review efforts toward the biological interpretation of the proteome.

  10. Endogenous Plasma Peptide Detection and Identification in the Rat by a Combination of Fractionation Methods and Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Fabrice Bertile

    2007-01-01

    Full Text Available Mass spectrometry-based analyses are essential tools in the field of biomarker research. However, detection and characterization of plasma low abundance and/or low molecular weight peptides is challenged by the presence of highly abundant proteins, salts and lipids. Numerous strategies have already been tested to reduce the complexity of plasma samples. The aim of this study was to enrich the low molecular weight fraction of rat plasma. To this end, we developed and compared simple protocols based on membrane filtration, solid phase extraction, and a combination of both. As assessed by UV absorbance, an albumin depletion 99% was obtained. The multistep fractionation strategy (including reverse phase HPLC allowed detection, in a reproducible manner (CV [1] 30%–35%, of more than 450 peaks below 3000 Da by MALDI-TOF/MS. A MALDI-TOF/MS-determined LOD as low as 1 fmol/μL was obtained, thus allowing nanoLC-Chip/ MS/MS identification of spiked peptides representing ∼10–6% of total proteins, by weight. Signal peptide recovery ranged between 5%–100% according to the spiked peptide considered. Tens of peptide sequence tags from endogenous plasma peptides were also obtained and high confidence identifications of low abundance fibrinopeptide A and B are reported here to show the efficiency of the protocol. It is concluded that the fractionation protocol presented would be of particular interest for future differential (high throughput analyses of the plasma low molecular weight fraction.

  11. Continuous-flow isotope ratio mass spectrometry method for carbon and hydrogen isotope measurements on atmospheric methane

    Directory of Open Access Journals (Sweden)

    M. Brass

    2010-12-01

    Full Text Available We describe a continuous-flow isotope ratio mass spectrometry (CF-IRMS technique for high-precision δD and δ13C measurements of atmospheric methane on 40 mL air samples. CH4 is separated from other air components by utilizing purely physical processes based on temperature, time and mechanical valve switching. Chemical agents are avoided. Trace amounts of interfering compounds can be separated by gas chromatography after pre-concentration of the CH4 sample. The purified sample is then either combusted to CO2 or pyrolyzed to H2 for stable isotope measurement. Apart from connecting samples and refilling liquid nitrogen as coolant the system is fully automated and allows an unobserved, continuous analysis of samples. The analytical system has been used for analysis of air samples with CH4 mixing ratios between ~100 and ~10 000 ppb, for higher mixing ratios samples usually have to be diluted.

  12. An optimized two-step derivatization method for analyzing diethylene glycol ozonation products using gas chromatography and mass spectrometry.

    Science.gov (United States)

    Yu, Ran; Duan, Lei; Jiang, Jingkun; Hao, Jiming

    2017-03-01

    The ozonation of hydroxyl compounds (e.g., sugars and alcohols) gives a broad range of products such as alcohols, aldehydes, ketones, and carboxylic acids. This study developed and optimized a two-step derivatization procedure for analyzing polar products of aldehydes and carboxylic acids from the ozonation of diethylene glycol (DEG) in a non-aqueous environment using gas chromatography-mass spectrometry. Experiments based on Central Composite Design with response surface methodology were carried out to evaluate the effects of derivatization variables and their interactions on the analysis. The most desirable derivatization conditions were reported, i.e., oximation was performed at room temperature overnight with the o-(2,3,4,5,6-pentafluorobenzyl) hydroxyl amine to analyte molar ratio of 6, silylation reaction temperature of 70°C, reaction duration of 70min, and N,O-bis(trimethylsilyl)-trifluoroacetamide volume of 12.5μL. The applicability of this optimized procedure was verified by analyzing DEG ozonation products in an ultrafine condensation particle counter simulation system. Copyright © 2016. Published by Elsevier B.V.

  13. Fragmentation of molecular ions in differential mobility spectrometry as a method for identification of chemical warfare agents.

    Science.gov (United States)

    Maziejuk, M; Puton, J; Szyposzyńska, M; Witkiewicz, Z

    2015-11-01

    The subject of the work is the use of differential mobility spectrometry (DMS) for the detection of chemical warfare agents (CWA). Studies were performed for mustard gas, i.e., bis(2-chloroethyl)sulfide (HD), sarin, i.e., O-isopropyl methylphosphonofluoridate (GB) and methyl salicylate (MS) used as test compounds. Measurements were conducted with two ceramic DMS analyzers of different constructions allowing the generation of an electric field with an intensity of more than 120 Td. Detector signals were measured for positive and negative modes of operation in a temperature range from 0 to 80 °C. Fragmentations of ions containing analyte molecules were observed for all tested compounds. The effective temperatures of fragmentation estimated on the basis of dispersion plots were equal from about 148 °C for GB to 178 °C for MS. It was found that values of separation voltage (SV) and compensation voltage (CV) at which the fragmentation of sample ions is observed may be the parameters improving the certainty of detection for different analytes. The DMS analyzers enabling the observation of ion fragmentation can be successfully used for effective CWA detection. Copyright © 2015. Published by Elsevier B.V.

  14. A NEW METHOD OF PEAK DETECTION FOR ANALYSIS OF COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY MASS SPECTROMETRY DATA.

    Science.gov (United States)

    Kim, Seongho; Ouyang, Ming; Jeong, Jaesik; Shen, Changyu; Zhang, Xiang

    2014-06-01

    We develop a novel peak detection algorithm for the analysis of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOF MS) data using normal-exponential-Bernoulli (NEB) and mixture probability models. The algorithm first performs baseline correction and denoising simultaneously using the NEB model, which also defines peak regions. Peaks are then picked using a mixture of probability distribution to deal with the co-eluting peaks. Peak merging is further carried out based on the mass spectral similarities among the peaks within the same peak group. The algorithm is evaluated using experimental data to study the effect of different cut-offs of the conditional Bayes factors and the effect of different mixture models including Poisson, truncated Gaussian, Gaussian, Gamma, and exponentially modified Gaussian (EMG) distributions, and the optimal version is introduced using a trial-and-error approach. We then compare the new algorithm with two existing algorithms in terms of compound identification. Data analysis shows that the developed algorithm can detect the peaks with lower false discovery rates than the existing algorithms, and a less complicated peak picking model is a promising alternative to the more complicated and widely used EMG mixture models.

  15. A NEW METHOD OF PEAK DETECTION FOR ANALYSIS OF COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY MASS SPECTROMETRY DATA*

    Science.gov (United States)

    Kim, Seongho; Ouyang, Ming; Jeong, Jaesik; Shen, Changyu; Zhang, Xiang

    2014-01-01

    We develop a novel peak detection algorithm for the analysis of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOF MS) data using normal-exponential-Bernoulli (NEB) and mixture probability models. The algorithm first performs baseline correction and denoising simultaneously using the NEB model, which also defines peak regions. Peaks are then picked using a mixture of probability distribution to deal with the co-eluting peaks. Peak merging is further carried out based on the mass spectral similarities among the peaks within the same peak group. The algorithm is evaluated using experimental data to study the effect of different cut-offs of the conditional Bayes factors and the effect of different mixture models including Poisson, truncated Gaussian, Gaussian, Gamma, and exponentially modified Gaussian (EMG) distributions, and the optimal version is introduced using a trial-and-error approach. We then compare the new algorithm with two existing algorithms in terms of compound identification. Data analysis shows that the developed algorithm can detect the peaks with lower false discovery rates than the existing algorithms, and a less complicated peak picking model is a promising alternative to the more complicated and widely used EMG mixture models. PMID:25264474

  16. A single-aliquot regenerative-dose method based on IR (1.49 eV) bleaching of the fast OSL component in quartz

    DEFF Research Database (Denmark)

    Jain, M.; Murray, A.S.; Bøtter-Jensen, L.

    2005-01-01

    In the optically stimulated luminescence (OSL) dating of quartz, the presence of significant medium and slow components in the initial-OSL signal (first 0.8 s or so) can give rise to erroneous dose estimates. Thus it is desirable to develop a dose estimation method that is based on the OSL from t...

  17. Compound-Specific Chlorine Isotope Analysis of Tetrachloromethane and Trichloromethane by Gas Chromatography-Isotope Ratio Mass Spectrometry vs Gas Chromatography-Quadrupole Mass Spectrometry: Method Development and Evaluation of Precision and Trueness.

    Science.gov (United States)

    Heckel, Benjamin; Rodríguez-Fernández, Diana; Torrentó, Clara; Meyer, Armin; Palau, Jordi; Domènech, Cristina; Rosell, Mònica; Soler, Albert; Hunkeler, Daniel; Elsner, Martin

    2017-03-21

    Compound-specific chlorine isotope analysis of tetrachloromethane (CCl 4 ) and trichloromethane (CHCl 3 ) was explored by both, gas chromatography-isotope ratio mass spectrometry (GC-IRMS) and GC-quadrupole MS (GC-qMS), where GC-qMS was validated in an interlaboratory comparison between Munich and Neuchâtel with the same type of commercial GC-qMS instrument. GC-IRMS measurements analyzed CCl isotopologue ions, whereas GC-qMS analyzed the isotopologue ions CCl 3 , CCl 2 , CCl (of CCl 4 ) and CHCl 3 , CHCl 2 , CHCl (of CHCl 3 ), respectively. Lowest amount dependence (good linearity) was obtained (i) in H-containing fragment ions where interference of 35 Cl- to 37 Cl-containing ions was avoided; (ii) with tuning parameters favoring one predominant rather than multiple fragment ions in the mass spectra. Optimized GC-qMS parameters (dwell time 70 ms, 2 most abundant ions) resulted in standard deviations of 0.2‰ (CHCl 3 ) and 0.4‰ (CCl 4 ), which are only about twice as large as 0.1‰ and 0.2‰ for GC-IRMS. To compare also the trueness of both methods and laboratories, samples from CCl 4 and CHCl 3 degradation experiments were analyzed and calibrated against isotopically different reference standards for both CCl 4 and CHCl 3 (two of each). Excellent agreement confirms that true results can be obtained by both methods provided that a consistent set of isotopically characterized reference materials is used.

  18. Application of a rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of bumetanide in human plasma for a bioequivalence study.

    Science.gov (United States)

    Patel, Dinesh S; Sharma, Naveen; Patel, Mukesh C; Patel, Bhavin N; Shrivastav, Pranav S; Sanyal, Mallika

    2012-07-01

    A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been proposed for the determination of bumetanide in human plasma using tamsulosin as internal standard (IS). The analyte and IS were extracted from 200 μL of human plasma via solid phase extraction and the chromatographic separation was achieved on Peerless Basic C18 (100 mm × 4.6 mm, 3 μm) column under isocratic conditions. Detection of bumetanide and IS was done by tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for bumetanide and IS were m/z 365.2→240.2 and 409.2→228.2 respectively. The method was fully validated as per the US FDA guidelines. The limit of detection and lower limit of quantitation of the method were 0.03 and 0.30 ng/mL respectively with a linear dynamic range of 0.30-200.0 ng/mL for bumetanide. The intra-batch and inter-batch precision (% CV) was ≤6.9% while the mean extraction recovery was >90% across quality control levels. The method is selective in presence of four diuretic drugs and some commonly used medications by healthy volunteers. It was successfully applied to a bioequivalence study of 2mg bumetanide tablet formulation in 10 healthy Indian male subjects under fasting condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 42 incurred samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Determining the amount of Br, Na and K in six wheat samples with neutron activation analysis (NAA) method in Arak, I.R. Iran

    International Nuclear Information System (INIS)

    Reza Pourimani; Khatoon Abasnejad; Khadijeh Ghanbarzadeh; Mohammad Reza Zare; Mahdi Kamali

    2013-01-01

    Accurate knowledge of the trace elemental concentrations in wheat and its products is of great importance from a nutritional point of view. In this study, six wheat samples were prepared from the agriculture research center of Arak named Sardari, Amir, MV-17, Batava, Karaj-2 and Alvand; they were analyzed by neutron activation method (NAA). In this method, Isfahan miniature reactor as a neutron source and relative NAA method has been used as the analysis type. In this design in order to record gamma spectrum the MCA system and high purity germanium detector were used. Finally, the concentration of the trace elements such as Br, K and Na value was determined for the Sardari, Amir, Alvand, MV-17, Batava, Karaj-2 wheat samples. The average concentration of trace elements in all wheat samples in the studied area are 2.41(0.8597-6.1175) mg kg -1 for Br, 13.42(8.7063-24.696) mg kg -1 for Na and 463.30(434.22-505.45) mg kg -1 for K, respectively. These were compared with other reports results. This study has been conducted as the first time for this region. (author)

  20. An effective method of UV-oxidation of dissolved organic carbon in natural waters for radiocarbon analysis by accelerator mass spectrometry

    Science.gov (United States)

    Xue, Yuejun; Ge, Tiantian; Wang, Xuchen

    2015-12-01

    Radiocarbon (14C) measurement of dissolved organic carbon (DOC) is a very powerful tool to study the sources, transformation and cycling of carbon in the ocean. The technique, however, remains great challenges for complete and successful oxidation of sufficient DOC with low blanks for high precision carbon isotopic ratio analysis, largely due to the overwhelming proportion of salts and low DOC concentrations in the ocean. In this paper, we report an effective UV-Oxidation method for oxidizing DOC in natural waters for radiocarbon analysis by accelerator mass spectrometry (AMS). The UV-oxidation system and method show 95%±4% oxidation efficiency and high reproducibility for DOC in both river and seawater samples. The blanks associated with the method was also low (about 3 µg C) that is critical for 14C analysis. As a great advantage of the method, multiple water samples can be oxidized at the same time so it reduces the sample processing time substantially compared with other UV-oxidation method currently being used in other laboratories. We have used the system and method for 14C studies of DOC in rivers, estuaries, and oceanic environments and have received promise results.

  1. A high-throughput screening method of bisphenols, bisphenols digycidyl ethers and their derivatives in dairy products by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cheng, Yan; Nie, Xue-Mei; Wu, Han-Qiu; Hong, Yun-He; Yang, Bing-Cheng; Liu, Tong; Zhao, Dan; Wang, Jian-Feng; Yao, Gui-Hong; Zhang, Feng

    2017-01-15

    A simple and universal analytical method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for high throughput screening of 21 bisphenols, bisphenols digycidyl ethers and their derivatives in dairy products was developed. Response Surface Methodology (RSM) was used to optimize sample preparation conditions based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) method. The analytes were extracted by using 15 mL acetonitrile with 1% acetic acid, and the extracts were further purified by using 190 mg of C18 and 390 mg of PSA. The extracts were analyzed by UHPLC-MS/MS with electrospray ionization (ESI) source. Linearity was assessed by using matrix-matched standard calibration and good correlation coefficients (r 2  > 0.99) were obtained. The limits of quantitation (LOQs) for the analytes ranged from 0.02 to 5 μg kg -1 . The extraction recoveries were in a range of 88.2%-108.2%. Good method reproducibility in terms of intra- and inter-day precision was observed, yielding relative standard deviations (RSDs) less than 8.9% and 9.9%, respectively. The validation method results revealed that the proposed method was sensitive and reliable. Finally, this method was successfully applied to dairy product analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Development of a method to measure the concentration of 14C in the stack air of nuclear power plants by accelerator mass spectrometry (AMS)

    International Nuclear Information System (INIS)

    Stenstroem, K.; Erlandsson, B.; Hellborg, R.; Haakansson, K.; Wiebert, A.; Skog, G.

    1993-04-01

    C-14, a pure low-energetic beta-emitter, is produced through various nuclear reactions in nuclear power plants. Some of this C-14 is air-borne and is transported via the ventilation system through the stack of the power station and is integrated in living matter in the surroundings of the plant. The long half-life of the isotope (T1/2=5730 years) and the biological importance of carbon may lead to a not negligible contribution of the radiation dose for those living in the neighbourhood of nuclear power plants. C-14 has earlier been measured radiometrically with mainly two different methods, using proportional counters or liquid scintillators. In this report a new method is described, using an accelerator based technique. accelerator mass spectrometry (AMS). This technique has at least three advantages over the radiometrical methods. It requires only a few litres of gas per sample, which is 100-1000 times less compared to the radiometrical methods. It is insensitive to the beta and gamma rays from other radioactive isotopes in the stack air. The measuring time with AMS, about 20 minutes per sample, is considerably shorter compared to the radiometrical methods, which demand several hours per sample. The integrity of the AMS method is high and it might be convenient for regulatory supervision. (22 refs.)

  3. A simultaneous screening and quantitative method for the multiresidue analysis of pesticides in spices using ultra-high performance liquid chromatography-high resolution (Orbitrap) mass spectrometry.

    Science.gov (United States)

    Goon, Arnab; Khan, Zareen; Oulkar, Dasharath; Shinde, Raviraj; Gaikwad, Suresh; Banerjee, Kaushik

    2018-01-12

    A novel screening and quantitation method is reported for non-target multiresidue analysis of pesticides using ultra-HPLC-quadrupole-Orbitrap mass spectrometry in spice matrices, including black pepper, cardamom, chili, coriander, cumin, and turmeric. The method involved sequential full-scan (resolution = 70,000), and variable data independent acquisition (vDIA) with nine consecutive fragmentation events (resolution = 17,500). Samples were extracted by the QuEChERS method. The introduction of an SPE-based clean-up step through hydrophilic-lipophilic-balance (HLB) cartridges proved advantageous in minimizing the false negatives. For coriander, cumin, chili, and cardamom, the screening detection limit was largely at 2 ng/g, while it was 5 ng/g for black pepper, and turmeric. When the method was quantitatively validated for 199 pesticides, the limit of quantification (LOQ) was mostly at 10 ng/g (excluding black pepper, and turmeric with LOQ = 20 ng/g) with recoveries within 70-120%, and precision-RSDs <20%. Furthermore, the method allowed the identification of suspected non-target analytes through retrospective search of the accurate mass of the compound-specific precursor and product ions. Compared to LC-MS/MS, the quantitative performance of this Orbitrap-MS method had agreements in residue values between 78-100%. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography–mass spectrometry and stable labeled isotope as internal standard

    International Nuclear Information System (INIS)

    Varlet, V.; Smith, F.; Froidmont, S. de; Dominguez, A.; Rinaldi, A.; Augsburger, M.; Mangin, P.; Grabherr, S.

    2013-01-01

    Graphical abstract: -- Highlights: •We developed a method for CO 2 analysis in cardiac samples and quantification by 13 CO 2 . •This method was fully validated by accuracy profile. •We have applied this method to perform CO 2 precise quantification for forensic applications. •Context of the death could be documented following CO 2 concentrations. -- Abstract: A novel approach to measure carbon dioxide (CO 2 ) in gaseous samples, based on a precise and accurate quantification by 13 CO 2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography–mass spectrometry (HS-GC–MS) method applicable in the routine determination of CO 2 . The main drawback of the GC methods discussed in the literature for CO 2 measurement is the lack of a specific internal standard necessary to perform quantification. CO 2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ( 13 CO 2 ) on the basis of the stoichiometric formation of CO 2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH 13 CO 3 ). This method allows a precise measurement of CO 2 concentration and was validated on various human postmortem gas samples in order to study its efficiency

  5. Multiresidue method for detection of pesticides in beef meat using liquid chromatography coupled to mass spectrometry detection (LC-MS) after QuEChERS extraction.

    Science.gov (United States)

    Oliveira, Fabiano Aurélio da Silva; Pereira, Elba Nathália Corrêa; Gobbi, Jennifer Mattedi; Soto-Blanco, Benito; Melo, Marília Martins

    2018-01-01

    Beef meat is an important food that can be contaminated by pesticides. This study aimed to optimize a multiresidue method for identification and quantification of pesticides in beef meat by liquid chromatography coupled to mass spectrometry detection (LC-MS). The extraction and clean-up procedures were adapted from the QuECHERS method. From the 188 analytes tested, the method was validated as qualitative method for 19 compounds and as quantitative method for 152 compounds. The results were satisfactory, yielding coefficients of variation of less than 20% and recoveries ranging from 70% to 120% and expanded uncertainty of less than 50%. The quantification limit was typically 10 µg kg -1 (but 25 µg kg -1 for 12 of the compounds) and the detection limit was 5.0 µg kg -1 . Thirty-two real samples of commercialized beef meat were analyzed without any residual pesticide being found. Thus, the results showed that the multiresidue method for detecting 171 pesticides, using adapted QuECHERS for extraction and LC-MS for detection, is suitable for analyzing beef meat.

  6. An Object-Based Image Analysis Method for Monitoring Land Conversion by Artificial Sprawl Use of RapidEye and IRS Data

    Directory of Open Access Journals (Sweden)

    Maud Balestrat

    2012-02-01

    Full Text Available In France, in the peri-urban context, urban sprawl dynamics are particularly strong with huge population growth as well as a land crisis. The increase and spreading of built-up areas from the city centre towards the periphery takes place to the detriment of natural and agricultural spaces. The conversion of land with agricultural potential is all the more worrying as it is usually irreversible. The French Ministry of Agriculture therefore needs reliable and repeatable spatial-temporal methods to locate and quantify loss of land at both local and national scales. The main objective of this study was to design a repeatable method to monitor land conversion characterized by artificial sprawl: (i We used an object-based image analysis to extract artificial areas from satellite images; (ii We built an artificial patch that consists of aggregating all the peripheral areas that characterize artificial areas. The “artificialized” patch concept is an innovative extension of the urban patch concept, but differs in the nature of its components and in the continuity distance applied; (iii The diachronic analysis of artificial patch maps enables characterization of artificial sprawl. The method was applied at the scale of four departments (similar to provinces along the coast of Languedoc-Roussillon, in the South of France, based on two satellite datasets, one acquired in 1996–1997 (Indian Remote Sensing and the other in 2009 (RapidEye. In the four departments, we measured an increase in artificial areas of from 113,000 ha in 1997 to 133,000 ha in 2009, i.e., an 18% increase in 12 years. The package comes in the form of a 1/15,000 valid cartography, usable at the scale of a commune (the smallest territorial division used for administrative purposes in France that can be adapted to departmental and regional scales. The method is reproducible in homogenous spatial-temporal terms, so that it could be used periodically to assess changes in land conversion

  7. Final LDRD report : development of sample preparation methods for ChIPMA-based imaging mass spectrometry of tissue samples.

    Energy Technology Data Exchange (ETDEWEB)

    Maharrey, Sean P.; Highley, Aaron M.; Behrens, Richard, Jr.; Wiese-Smith, Deneille

    2007-12-01

    The objective of this short-term LDRD project was to acquire the tools needed to use our chemical imaging precision mass analyzer (ChIPMA) instrument to analyze tissue samples. This effort was an outgrowth of discussions with oncologists on the need to find the cellular origin of signals in mass spectra of serum samples, which provide biomarkers for ovarian cancer. The ultimate goal would be to collect chemical images of biopsy samples allowing the chemical images of diseased and nondiseased sections of a sample to be compared. The equipment needed to prepare tissue samples have been acquired and built. This equipment includes an cyro-ultramicrotome for preparing thin sections of samples and a coating unit. The coating unit uses an electrospray system to deposit small droplets of a UV-photo absorbing compound on the surface of the tissue samples. Both units are operational. The tissue sample must be coated with the organic compound to enable matrix assisted laser desorption/ionization (MALDI) and matrix enhanced secondary ion mass spectrometry (ME-SIMS) measurements with the ChIPMA instrument Initial plans to test the sample preparation using human tissue samples required development of administrative procedures beyond the scope of this LDRD. Hence, it was decided to make two types of measurements: (1) Testing the spatial resolution of ME-SIMS by preparing a substrate coated with a mixture of an organic matrix and a bio standard and etching a defined pattern in the coating using a liquid metal ion beam, and (2) preparing and imaging C. elegans worms. Difficulties arose in sectioning the C. elegans for analysis and funds and time to overcome these difficulties were not available in this project. The facilities are now available for preparing biological samples for analysis with the ChIPMA instrument. Some further investment of time and resources in sample preparation should make this a useful tool for chemical imaging applications.

  8. An integrated native mass spectrometry and top-down proteomics method that connects sequence to structure and function of macromolecular complexes

    Science.gov (United States)

    Li, Huilin; Nguyen, Hong Hanh; Ogorzalek Loo, Rachel R.; Campuzano, Iain D. G.; Loo, Joseph A.

    2018-02-01

    Mass spectrometry (MS) has become a crucial technique for the analysis of protein complexes. Native MS has traditionally examined protein subunit arrangements, while proteomics MS has focused on sequence identification. These two techniques are usually performed separately without taking advantage of the synergies between them. Here we describe the development of an integrated native MS and top-down proteomics method using Fourier-transform ion cyclotron resonance (FTICR) to analyse macromolecular protein complexes in a single experiment. We address previous concerns of employing FTICR MS to measure large macromolecular complexes by demonstrating the detection of complexes up to 1.8 MDa, and we demonstrate the efficacy of this technique for direct acquirement of sequence to higher-order structural information with several large complexes. We then summarize the unique functionalities of different activation/dissociation techniques. The platform expands the ability of MS to integrate proteomics and structural biology to provide insights into protein structure, function and regulation.

  9. A simple method of correcting for variation of sample thickness in the determination of the activity of environmental samples by gamma spectrometry

    International Nuclear Information System (INIS)

    Galloway, R.B.

    1991-01-01

    Gamma ray spectrometry is a well established method of determining the activity of radioactive components in environmental samples. It is usual to maintain precisely the same counting geometry in measurements on samples under investigation as in the calibration measurements on standard materials of known activity, thus avoiding perceived uncertainties and complications in correcting for changes in counting geometry. However this may not always be convenient if, as on some occasions, only a small quantity of sample material is available for analysis. A procedure which avoids re-calibration for each sample size is described and is shown to be simple to use without significantly reducing the accuracy of measurement of the activity of typical environmental samples. The correction procedure relates to the use of cylindrical samples at a constant distance from the detector, the samples all having the same diameter but various thicknesses being permissible. (author)

  10. Thermal transformation of bioactive caffeic acid on fumed silica seen by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry and quantum chemical methods.

    Science.gov (United States)

    Kulik, Tetiana V; Lipkovska, Natalia O; Barvinchenko, Valentyna M; Palyanytsya, Borys B; Kazakova, Olga A; Dudik, Olesia O; Menyhárd, Alfréd; László, Krisztina

    2016-05-15

    Thermochemical studies of hydroxycinnamic acid derivatives and their surface complexes are important for the pharmaceutical industry, medicine and for the development of technologies of heterogeneous biomass pyrolysis. In this study, structural and thermal transformations of caffeic acid complexes on silica surfaces were studied by UV-Vis spectroscopy, thermogravimetric analysis, temperature programmed desorption mass spectrometry (TPD MS) and quantum chemical methods. Two types of caffeic acid surface complexes are found to form through phenolic or carboxyl groups. The kinetic parameters of the chemical reactions of caffeic acid on silica surface are calculated. The mechanisms of thermal transformations of the caffeic chemisorbed surface complexes are proposed. Thermal decomposition of caffeic acid complex chemisorbed through grafted ester group proceeds via three parallel reactions, producing ketene, vinyl and acetylene derivatives of 1,2-dihydroxybenzene. Immobilization of phenolic acids on the silica surface improves greatly their thermal stability. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    International Nuclear Information System (INIS)

    Nam, Sang-Ho; Kim, Jae-Jin; Chung, Yong-Sam; Kim, Sun-Ha

    2003-01-01

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

  12. Development of a Multi-class Steroid Hormone Screening Method using Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS)

    Science.gov (United States)

    Boggs, Ashley S. P.; Bowden, John A.; Galligan, Thomas M.; Guillette, Louis J.; Kucklick, John R.

    2016-01-01

    Monitoring complex endocrine pathways is often limited by indirect measurement or measurement of a single hormone class per analysis. There is a burgeoning need to develop specific direct-detection methods capable of providing simultaneous measurement of biologically relevant concentrations of multiple classes of hormones (estrogens, androgens, progestogens, and corticosteroids). The objectives of this study were to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for multi-class steroid hormone detection using biologically relevant concentrations, then test limits of detection (LOD) in a high-background matrix by spiking charcoal-stripped fetal bovine serum (FBS) extract. Accuracy was tested with National Institute of Standards and Technology Standard Reference Materials (SRMs) with certified concentrations of cortisol, testosterone, and progesterone. 11-Deoxycorticosterone, 11-deoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, adrenosterone, androstenedione, cortisol, corticosterone, dehydroepiandrosterone, dihydrotestosterone, estradiol, estriol, estrone, equilin, pregnenolone, progesterone, and testosterone were also measured using isotopic dilution. Dansyl chloride (DC) derivatization was investigated maintaining the same method to improve and expedite estrogen analysis. Biologically relevant LODs were determined for 15 hormones. DC derivatization improved estrogen response two- to eight-fold, and improved chromatographic separation. All measurements had an accuracy ≤ 14 % difference from certified values (not accounting for uncertainty) and relative standard deviation ≤ 14 %. This method chromatographically separated and quantified biologically relevant concentrations of four hormone classes using highly specific fragmentation patterns and measured certified values of hormones that were previously split into three separate chromatographic methods. PMID:27039201

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

    Science.gov (United States)

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

    2018-05-01

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

  14. Evaluation of fundamental parameters method for biological materials and soil analysis by energy dispersive x-ray spectrometry

    International Nuclear Information System (INIS)

    Holynska, B.; Muia, L.M.; Maina, D.M.

    1987-01-01

    Two methods of determination of trace elements in plant materials, viz. the fundamental parameters method (FPM) and the empirical method with the use of standard samples, were compared. Hay CRM and fresh tea leaves were used in measurements. Good agreement was achieved for the determination of a number of elements by both methods. Also Soil-7 Certified Reference Material (CRM) was analysed using emission-transmission method for absorption correction and FPM for concentration determination. The agreement with CRM was found to be reasonably good for several elements. (author)

  15. Evaluation of fundamental parameters method for biological materials and soil analysis by energy dispersive x-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Holynska, B; Muia, L M; Maina, D M

    1987-01-01

    Two methods of determination of trace elements in plant materials, viz. the fundamental parameters method (FPM) and the empirical method with the use of standard samples, were compared. Hay CRM and fresh tea leaves were used in measurements. Good agreement was achieved for the determination of a number of elements by both methods. Also Soil-7 Certified Reference Material (CRM) was analysed using emission-transmission method for absorption correction and FPM for concentration determination. The agreement with CRM was found to be reasonably good for several elements.

  16. NaIrO3-A pentavalent post-perovskite

    International Nuclear Information System (INIS)

    Bremholm, M.; Dutton, S.E.; Stephens, P.W.; Cava, R.J.

    2011-01-01

    Sodium iridium (V) oxide, NaIrO 3, was synthesized by a high pressure solid state method and recovered to ambient conditions. It is found to be isostructural with CaIrO 3 , the much-studied structural analog of the high-pressure post-perovskite phase of MgSiO 3 . Among the oxide post-perovskites, NaIrO 3 is the first example with a pentavalent cation. The structure consists of layers of corner- and edge-sharing IrO 6 octahedra separated by layers of NaO 8 bicapped trigonal prisms. NaIrO 3 shows no magnetic ordering and resistivity measurements show non-metallic behavior. The crystal structure, electrical and magnetic properties are discussed and compared to known post-perovskites and pentavalent perovskite metal oxides. -- Graphical abstract: Sodium iridium(V) oxide, NaIrO 3 , synthesized by a high pressure solid state method and recovered to ambient conditions is found to crystallize as the post-perovskite structure and is the first example of a pentavalent ABO 3 post-perovskite. Research highlights: → NaIrO 3 post-perovskite stabilized by pressure. → First example of a pentavalent oxide post-perovskite. → Non-metallic and non-magnetic behavior of NaIrO 3 .

  17. Reference peak method for analysis of doublets in gamma-ray spectrometry used in neutron activation analysis

    International Nuclear Information System (INIS)

    Wasek, M.; Cichowlas, A.; Sterlinski, S.; Dybczynski, R.

    2000-01-01

    A simple algebraic method for the quantitative analysis of doublets in gamma-ray spectra from HPGe detectors is presented. The calculation algorithm is accomplished using the Microsoft Excel program. The method does not require any assumptions regarding the shape of the peaks in the spectrum. The possibilities of quantitative analysis of doublets of various intensity ration and separation of ots components are discussed in detail. The practical examples proved the usefulness the method also for the analysis of the closed doublets. (author)

  18. A Rapid Magnetic Solid Phase Extraction Method Followed by Liquid Chromatography-Tandem Mass Spectrometry Analysis for the Determination of Mycotoxins in Cereals.

    Science.gov (United States)

    Barbera, Giorgia La; Capriotti, Anna Laura; Cavaliere, Chiara; Foglia, Patrizia; Montone, Carmela Maria; Chiozzi, Riccardo Zenezini; Laganà, Aldo

    2017-04-21

    Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE), a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high-performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were >60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes.

  19. Quantification of imatinib in human serum: validation of a high-performance liquid chromatography-mass spectrometry method for therapeutic drug monitoring and pharmacokinetic assays.

    Science.gov (United States)

    Rezende, Vinicius Marcondes; Rivellis, Ariane; Novaes, Mafalda Megumi Yoshinaga; de Alencar Fisher Chamone, Dalton; Bendit, Israel

    2013-01-01

    Imatinib mesylate has been a breakthrough treatment for chronic myeloid leukemia. It has become the ideal tyrosine kinase inhibitor and the standard treatment for chronic-phase leukemia. Striking results have recently been reported, but intolerance to imatinib and noncompliance with treatment remain to be solved. Molecular monitoring by quantitative real-time polymerase chain reaction is the gold standard for monitoring patients, and imatinib blood levels have also become an important tool for monitoring. A fast and cheap method was developed and validated using high-performance liquid chromatography-mass spectrometry for quantification of imatinib in human serum and tamsulosin as the internal standard. Remarkable advantages of the method includes use of serum instead of plasma, less time spent on processing and analysis, simpler procedures, and requiring reduced amounts of biological material, solvents, and reagents. Stability of the analyte was also studied. This research also intended to drive the validation scheme in clinical centers. The method was validated according to the requirements of the US Food and Drug Administration and Brazilian National Health Surveillance Agency within the range of 0.500-10.0 μg/mL with a limit of detection of 0.155 μg/mL. Stability data for the analyte are also presented. Given that the validated method has proved to be linear, accurate, precise, and robust, it is suitable for pharmacokinetic assays, such as bioavailability and bioequivalence, and is being successfully applied in routine therapeutic drug monitoring in the hospital service.

  20. A simple and fast method for the inspection of preservatives in cheeses and cream by liquid chromatography- electrospray tandem mass spectrometry.

    Science.gov (United States)

    Molognoni, Luciano; de Sá Ploêncio, Leandro Antunes; Valese, Andressa Camargo; De Dea Lindner, Juliano; Daguer, Heitor

    2016-01-15

    In this work, a simplified extraction and short time of analysis method for the simultaneous determination of natamycin, nisin and sorbic acid in cheeses and cream by reverse phase liquid chromatography-electrospray-tandem mass spectrometry was developed. Full validation was performed according to the Commission Decision 2002/657/EC criteria and method applicability was checked on several samples, aiming to inspect their compliance with regulatory limits. The method was linear in the concentration ranges of 0-10mg kg(-1) (natamycin), 0-25mg kg(-1) (nisin) and 0 20mg kg(-1) (sorbic acid). Samples of the three most consumed types of cheese (fresh, pasta filata and ripened) in Brazil and cream (ultra high temperature and pasteurized, 20-30% fat content) were assessed. A surprising rate of non-compliance was observed, especially among ripened grated cheeses, since 80% of samples were above the maximum limit for sorbic acid with an average concentration of 2766.3±10.8mg kg(-1). Moreover, a major non-compliance for the cream samples was observed. The proposed method can be applied as an efficient tool for the inspection of preservatives in cheeses and cream. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. A standards-based method for compositional analysis by energy dispersive X-ray spectrometry using multivariate statistical analysis: application to multicomponent alloys.

    Science.gov (United States)

    Rathi, Monika; Ahrenkiel, S P; Carapella, J J; Wanlass, M W

    2013-02-01

    Given an unknown multicomponent alloy, and a set of standard compounds or alloys of known composition, can one improve upon popular standards-based methods for energy dispersive X-ray (EDX) spectrometry to quantify the elemental composition of the unknown specimen? A method is presented here for determining elemental composition of alloys using transmission electron microscopy-based EDX with appropriate standards. The method begins with a discrete set of related reference standards of known composition, applies multivariate statistical analysis to those spectra, and evaluates the compositions with a linear matrix algebra method to relate the spectra to elemental composition. By using associated standards, only limited assumptions about the physical origins of the EDX spectra are needed. Spectral absorption corrections can be performed by providing an estimate of the foil thickness of one or more reference standards. The technique was applied to III-V multicomponent alloy thin films: composition and foil thickness were determined for various III-V alloys. The results were then validated by comparing with X-ray diffraction and photoluminescence analysis, demonstrating accuracy of approximately 1% in atomic fraction.

  2. Liquid chromatography-tandem mass spectrometry method for the analysis of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine, a biocidal disinfectant, in dairy products.

    Science.gov (United States)

    Slimani, Kahina; Pirotais, Yvette; Maris, Pierre; Abjean, Jean-Pierre; Hurtaud-Pessel, Dominique

    2018-10-01

    A novel and reliable method to quantify residual levels of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in dairy products using ion-pairing reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. Sample extraction was done with salting-out technique using acetonitrile and sodium chloride. For LC-MS/MS, the analyte was detected using positive electrospray ionization (ESI+) and two multiple reaction monitoring (MRM) transitions were monitored. The method was validated in the 5-150 µg kg -1 range using total error approach. Thus, performance criteria of the method were evaluated. Relative standard deviations for trueness and precision were lower than 10%; with the exception of hard pressed cheese at 5 µg kg -1 for precision. The limit of quantification (LOQ) was around 5-7 µg kg -1 depending on the matrix of interest. The method was successfully applied to accurately quantify N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in 146 various dairy products with a maximum contamination level of 225 µg kg -1 in cheese. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Toward a high-throughput method for determining vicine and convicine levels in faba bean seeds using flow injection analysis combined with tandem mass spectrometry.

    Science.gov (United States)

    Purves, Randy W; Khazaei, Hamid; Vandenberg, Albert

    2018-08-01

    Although faba bean provides environmental and health benefits, vicine and convicine (v-c) limit its use as a source of vegetable protein. Crop improvement efforts to minimize v-c concentration require low-cost, rapid screening methods to distinguish between high and low v-c genotypes to accelerate development of new cultivars and to detect out-crossing events. To assist crop breeders, we developed a unique and rapid screening method that uses a 60 s instrumental analysis step to accurately distinguish between high and low v-c genotypes. The method involves flow injection analysis (FIA) coupled with tandem mass spectrometry (i.e., selective reaction monitoring, SRM). Using seeds with known v-c levels as calibrants, measured v-c levels were comparable with liquid chromatography (LC)-SRM results and the method was used to screen 370 faba bean genotypes. Widespread use of FIA-SRM will accelerate breeding of low v-c faba bean, thereby alleviating concerns about anti-nutritional effects of v-c in this crop. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Method validation for determination of metals in Vitis labrusca L. grapevine leaf extracts by inductively coupled plasma mass spectrometry (ICP-MS

    Directory of Open Access Journals (Sweden)

    LIANE V.V. BOKOWSKI

    Full Text Available ABSTRACT Vitis labrusca L. is the main species used for wine and juice production in Brazil. The grapevine leaves can be used both as functional foods and as cheapest sources for the extraction of phenolic compounds. Besides the antioxidant activity, grapevine leaves exhibited significant anti-inflammatory activity. Therefore, the aim of this study was to develop and validate an analytical methodology to determine the metals selenium (96Se, chromium (53Cr, nickel (62Ni, cadmium (111Cd and lead (206Pb in 30 samples of grapevine leaf extracts (Vitis labrusca, Bordo cultivar using inductively coupled plasma mass spectrometry (ICP-MS. To obtain the grapevine leaf extracts the samples were milled, weighed and digested in microwave oven with nitric acid. The method showed linearity, precision, accuracy and limits of quantification and detection acceptable for INMETRO protocol validation of analytical methods. Therefore, the method using ICP-MS was developed and validated to determine metals concentrations in grapevine leaves of Vitis labrusca L. and the proposed method could be applied in routine analytical laboratory.

  5. A novel liquid chromatography-tandem mass spectrometry method for determination of menadione in human plasma after derivatization with 3-mercaptopropionic acid.

    Science.gov (United States)

    Liu, Ruijuan; Wang, Mengmeng; Ding, Li

    2014-10-01

    Menadione (VK3), an essential fat-soluble naphthoquinone, takes very important physiological and pathological roles, but its detection and quantification is challenging. Herein, a new method was developed for quantification of VK3 in human plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after derivatization with 3-mercaptopropionic acid via Michael addition reaction. The derivative had been identified by the mass spectra and the derivatization conditions were optimized by considering different parameters. The method was demonstrated with high sensitivity and a low limit of quantification of 0.03 ng mL(-1) for VK3, which is about 33-fold better than that for the direct analysis of the underivatized compound. The method also had good precision and reproducibility. It was applied in the determination of basal VK3 in human plasma and a clinical pharmacokinetic study of menadiol sodium diphosphate. Furthermore, the method for the quantification of VK3 using LC-MS/MS was reported in this paper for the first time, and it will provide an important strategy for the further research on VK3 and menadione analogs. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Simultaneous monitoring of oxidation, deamidation, isomerization, and glycosylation of monoclonal antibodies by liquid chromatography-mass spectrometry method with ultrafast tryptic digestion.

    Science.gov (United States)

    Wang, Yi; Li, Xiaojuan; Liu, Yan-Hui; Richardson, Daisy; Li, Huijuan; Shameem, Mohammed; Yang, Xiaoyu

    Monoclonal antibodies are subjected to a wide variety of post-translational modifications (PTMs) that cause structural heterogeneity. Characterization and control of these modifications or quality attributes are critical to ensure antibody quality and to define any potential effects on the ultimate safety and potency of antibody therapeutics. The biopharmaceutical industry currently uses numerous tools to analyze these quality attributes individually, which requires substantial time and resources. Here, we report a simple and ultrafast bottom-up liquid chromatography-mass spectrometry (uLC-MS) method with 5 min tryptic digestion to simultaneously analyze multiple modifications, including oxidation, deamidation, isomerization, glycation, glycosylation, and N-terminal pyro-glutamate formation, which can occur during antibody production in mammalian cell culture, during purification and/or on storage. Compared to commonly used preparation procedures, this uLC-MS method eliminates assay artifacts of falsely-increased Met oxidation, Asp isomerization, and Asn deamidation, a problem associated with long digestion times in conventional LC-MS methods. This simple, low artifact multi-attribute uLC-MS method can be used to quickly and accurately analyze samples at any stage of antibody drug development, in particular for clone and media selection during cell culture development.

  7. Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples.

    Science.gov (United States)

    Gerace, E; Salomone, A; Abbadessa, G; Racca, S; Vincenti, M

    2012-02-01

    A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid-liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration.

  8. Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples

    Directory of Open Access Journals (Sweden)

    E. Gerace

    2012-02-01

    Full Text Available A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid–liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration. Keywords: Anti-estrogens, Fast-GC/MS, Urine screening, Validation, Breast cancer

  9. A general screening method for doping agents in human urine by solid phase extraction and liquid chromatography/time-of-flight mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Kolmonen, Marjo [Forensic Toxicology Division, Department of Forensic Medicine, University of Helsinki (Finland) and Doping Control Laboratory, United Laboratories Ltd., Helsinki (Finland)]. E-mail: marjo.kolmonen@helsinki.fi; Leinonen, Antti [Doping Control Laboratory, United Laboratories Ltd., Helsinki (Finland); Pelander, Anna [Forensic Toxicology Division, Department of Forensic Medicine, University of Helsinki (Finland); Ojanperae, Ilkka [Forensic Toxicology Division, Department of Forensic Medicine, University of Helsinki (Finland)

    2007-02-28

    A general screening method based on solid phase extraction (SPE) and liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) was developed and investigated with 124 different doping agents, including stimulants, {beta}-blockers, narcotics, {beta}{sub 2}-adrenergic agonists, agents with anti-estrogenic activity, diuretics and cannabinoids. Mixed mode cation exchange/C8 cartridges were applied to SPE, and chromatography was based on gradient elution on a C18 column. Ionization of the analytes was achieved with electrospray ionization in the positive mode. Identification by LC/TOFMS was based on retention time, accurate mass and isotopic pattern. Validation of the method consisted of analysis of specificity, analytical recovery, limit of detection and repeatability. The minimum required performance limit (MRPL), established by World Anti-Doping Agency (WADA), was attained to 97 doping agents. The extraction recoveries varied between 33 and 98% and the median was 58%. Mass accuracy was always better than 5 ppm, corresponding to a maximum mass error of 0.7 mDa. The repeatability of the method for spiked urine samples, expressed as median of relative standard deviations (RSD%) at concentrations of MRPL and 10 times MRPL, were 14% and 9%, respectively. The suitability of the LC/TOFMS method for doping control was demonstrated with authentic urine samples.

  10. Confirmatory analysis method for zeranol, its metabolites and related mycotoxins in urine by liquid chromatography-negative ion electrospray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bennekom, E.O. van; Brouwer, L.; Laurant, E.H.M.; Hooijerink, H.; Nielen, M.W.F

    2002-11-25

    The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding {alpha}- and {beta}-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CC{alpha} and CC{beta} values of 0.02-0.30 and <1.0 ng ml{sup -1}, respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas chromatography high resolution mass spectrometry. Preliminary data show that following a simple matrix solid phase dispersion clean-up, liver samples from poultry will be amenable to this method as well.

  11. Confirmatory analysis method for zeranol, its metabolites and related mycotoxins in urine by liquid chromatography-negative ion electrospray tandem mass spectrometry

    International Nuclear Information System (INIS)

    Bennekom, E.O. van; Brouwer, L.; Laurant, E.H.M.; Hooijerink, H.; Nielen, M.W.F.

    2002-01-01

    The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding α- and β-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CCα and CCβ values of 0.02-0.30 and -1 , respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas chromatography high resolution mass spectrometry. Preliminary data show that following a simple matrix solid phase dispersion clean-up, liver samples from poultry will be amenable to this method as well

  12. A Rapid Magnetic Solid Phase Extraction Method Followed by Liquid Chromatography-Tandem Mass Spectrometry Analysis for the Determination of Mycotoxins in Cereals

    Directory of Open Access Journals (Sweden)

    Giorgia La Barbera

    2017-04-01

    Full Text Available Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE, a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high–performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were >60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes.

  13. Rapid identification of pathogens directly from blood culture bottles by Bruker matrix-assisted laser desorption laser ionization-time of flight mass spectrometry versus routine methods.

    Science.gov (United States)

    Jamal, Wafaa; Saleem, Rola; Rotimi, Vincent O

    2013-08-01

    The use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of microorganisms directly from blood culture is an exciting dimension to the microbiologists. We evaluated the performance of Bruker SepsiTyper kit™ (STK) for direct identification of bacteria from positive blood culture. This was done in parallel with conventional methods. Nonrepetitive positive blood cultures from 160 consecutive patients were prospectively evaluated by both methods. Of 160 positive blood cultures, the STK identified 114 (75.6%) isolates and routine conventional method 150 (93%). Thirty-six isolates were misidentified or not identified by the kit. Of these, 5 had score of >2.000 and 31 had an unreliable low score of <1.7. Four of 8 yeasts were identified correctly. The average turnaround time using the STK was 35 min, including extraction steps and 30:12 to 36:12 h with routine method. The STK holds promise for timely management of bacteremic patients. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Standard test method for analysis of urine for uranium-235 and uranium-238 isotopes by inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of the concentration of uranium-235 and uranium-238 in urine using Inductively Coupled Plasma-Mass Spectrometry. This test method can be used to support uranium facility bioassay programs. 1.2 This method detection limits for 235U and 238U are 6 ng/L. To meet the requirements of ANSI N13.30, the minimum detectable activity (MDA) of each radionuclide measured must be at least 0.1 pCi/L (0.0037 Bq/L). The MDA translates to 47 ng/L for 235U and 300 ng/L for 238U. Uranium– 234 cannot be determined at the MDA with this test method because of its low mass concentration level equivalent to 0.1 pCi/L. 1.3 The digestion and anion separation of urine may not be necessary when uranium concentrations of more than 100 ng/L are present. 1.4 Units—The values stated in picoCurie per liter units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1....

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

    Science.gov (United States)

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

    2017-03-01

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

  16. Untargeted LC-Q-TOF mass spectrometry method for the detection of adulterations in skimmed-milk powder

    NARCIS (Netherlands)

    Cordewener, J.H.G.; Luykx, D.M.A.M.; Frankhuizen, R.; Bremer, M.G.E.G.; Hooijerink, H.; America, A.H.P.

    2009-01-01

    A nontargeted protein identification method was developed to screen for adulterations in skimmed-milk powder (SMP). There are indications of falsified SMP content due to the addition of plant proteins. To demonstrate the reliability and accuracy of the developed comparative LC-MS method using a

  17. Methods of calculus for neutron spectrometry in proportional counters; Metodos de calculo para espectrometria de neutrones en contadores proporcionales

    Energy Technology Data Exchange (ETDEWEB)

    Butragueno, J L; Blazquez, J B; Barrado, J M

    1976-07-01

    Response functions for cylindrical proportional counters with hydrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Monte Carlo application and the other one analytica at all. Results of both methods have been compared. (Author)

  18. Evaluation of Derivative Ultraviolet Spectrometry for Determining Saccharin in Cola and Other Matrices: An Instrumental Methods Experiment.

    Science.gov (United States)

    Stolzberg, Richard J.

    1986-01-01

    Background information and experimental procedures are provided for an experiment in which three samples of saccharin (a nickel plating solution, a dilute cola drink, and a more concentrated cola drink) are analyzed and the data interpreted using five methods. Precision and accuracy are evaluated and the best method is selected. (JN)

  19. First results of Minimum Fisher Regularisation as unfolding method for JET NE213 liquid scintillator neutron spectrometry

    International Nuclear Information System (INIS)

    Mlynar, Jan; Adams, John M.; Bertalot, Luciano; Conroy, Sean

    2005-01-01

    At JET, the NE213 liquid scintillator is being validated as a diagnostic tool for spectral measurements of neutrons emitted from the plasma. Neutron spectra have to be unfolded from the measured pulse-height spectra, which is an ill-conditioned problem. Therefore, use of two independent unfolding methods allows for less ambiguity on the interpretation of the data. In parallel to the routine algorithm MAXED based on the Maximum Entropy method, the Minimum Fisher Regularisation (MFR) method has been introduced at JET. The MFR method, known from two-dimensional tomography applications, has proved to provide a new transparent tool to validate the JET neutron spectra measured with the NE213 liquid scintillators. In this article, the MFR method applicable to spectra unfolding is briefly explained. After a mention of MFR tests on phantom spectra experimental neutron spectra are presented that were obtained by applying MFR to NE213 data in selected JET experiments. The results tend to confirm MAXED observations

  20. Improvement of a sample preparation method assisted by sodium deoxycholate for mass-spectrometry-based shotgun membrane proteomics.

    Science.gov (United States)

    Lin, Yong; Lin, Haiyan; Liu, Zhonghua; Wang, Kunbo; Yan, Yujun

    2014-11-01

    In current shotgun-proteomics-based biological discovery, the identification of membrane proteins is a challenge. This is especially true for integral membrane proteins due to their highly hydrophobic nature and low abundance. Thus, much effort has been directed at sample preparation strategies such as use of detergents, chaotropes, and organic solvents. We previously described a sample preparation method for shotgun membrane proteomics, the sodium deoxycholate assisted method, which cleverly circumvents many of the challenges associated with traditional sample preparation methods. However, the method is associated with significant sample loss due to the slightly weaker extraction/solubilization ability of sodium deoxycholate when it is used at relatively low concentrations such as 1%. Hence, we present an enhanced sodium deoxycholate sample preparation strategy that first uses a high concentration of sodium deoxycholate (5%) to lyse membranes and extract/solubilize hydrophobic membrane proteins, and then dilutes the detergent to 1% for a more efficient digestion. We then applied the improved method to shotgun analysis of proteins from rat liver membrane enriched fraction. Compared with other representative sample preparation strategies including our previous sodium deoxycholate assisted method, the enhanced sodium deoxycholate method exhibited superior sensitivity, coverage, and reliability for the identification of membrane proteins particularly those with high hydrophobicity and/or multiple transmembrane domains. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.