Metabolic profiling of yeast culture using gas chromatography coupled with orthogonal acceleration accurate mass time-of-flight mass spectrometry: application to biomarker discovery.

Science.gov (United States)

Kondo, Elsuida; Marriott, Philip J; Parker, Rhiannon M; Kouremenos, Konstantinos A; Morrison, Paul; Adams, Mike

2014-01-07

Yeast and yeast cultures are frequently used as additives in diets of dairy cows. Beneficial effects from the inclusion of yeast culture in diets for dairy mammals have been reported, and the aim of this study was to develop a comprehensive analytical method for the accurate mass identification of the 'global' metabolites in order to differentiate a variety of yeasts at varying growth stages (Diamond V XP, Yea-Sacc and Levucell). Microwave-assisted derivatization for metabolic profiling is demonstrated through the analysis of differing yeast samples developed for cattle feed, which include a wide range of metabolites of interest covering a large range of compound classes. Accurate identification of the components was undertaken using GC-oa-ToFMS (gas chromatography-orthogonal acceleration-time-of-flight mass spectrometry), followed by principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) for data reduction and biomarker discovery. Semi-quantification (fold changes in relative peak areas) was reported for metabolites identified as possible discriminative biomarkers (p-value 2), including D-ribose (four fold decrease), myo-inositol (five fold increase), L-phenylalanine (three fold increase), glucopyranoside (two fold increase), fructose (three fold increase) and threitol (three fold increase) respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Potential of gas chromatography-orthogonal acceleration time-of-flight mass spectrometry (GC-oaTOFMS) in flavor research.

Science.gov (United States)

Fay, Laurent B; Newton, Anthony; Simian, Hervé; Robert, Fabien; Douce, David; Hancock, Peter; Green, Martin; Blank, Imre

2003-04-23

Gas chromatography-orthogonal acceleration time-of-flight mass spectrometry (GC-oaTOFMS) is an emerging technique offering a straightforward access to a resolving power up to 7000. This paper deals with the use of GC-oaTOFMS to identify the flavor components of a complex seafood flavor extract and to quantify furanones formed in model Maillard reactions. A seafood extract was selected as a representative example for complex food flavors and was previously analyzed using GC-quadrupole MS, leaving several molecules unidentified. GC-oaTOFMS analysis was focused on these unknowns to evaluate its potential in flavor research, particularly for determining exact masses. N-Methyldithiodimethylamine, 6-methyl-5-hepten-2-one, and tetrahydro-2,4-dimethyl-4H-pyrrolo[2,1-d]-1,3,5-dithiazine were successfully identified on the basis of the precise mass determination of their molecular ions and their major fragments. A second set of experiments was performed to test the capabilities of the GC-oaTOFMS for quantification. Calibration curves were found to be linear over a dynamic range of 10(3) for the quantification of furanones. The quantitative data obtained using GC-oaTOFMS confirmed earlier results that the formation of 4-hydroxy-2,5-dimethyl-3(2H)-furanone was favored in the xylose/glycine model reaction and 2(or 5)-ethyl-4-hydroxy-5(or 2)-methyl-3(2H)-furanone in the xylose/alanine model reaction. It was concluded that GC-oaTOFMS may become a powerful analytical tool for the flavor chemist for both identification and quantification purposes, the latter in particular when combined with stable isotope dilution assay.

A compact time-of-flight mass spectrometer for ion source characterization

International Nuclear Information System (INIS)

Chen, L.; Wan, X.; Jin, D. Z.; Tan, X. H.; Huang, Z. X.; Tan, G. B.

2015-01-01

A compact time-of-flight mass spectrometer with overall dimension of about 413 × 250 × 414 mm based on orthogonal injection and angle reflection has been developed for ion source characterization. Configuration and principle of the time-of-flight mass spectrometer are introduced in this paper. The mass resolution is optimized to be about 1690 (FWHM), and the ion energy detection range is tested to be between about 3 and 163 eV with the help of electron impact ion source. High mass resolution and compact configuration make this spectrometer useful to provide a valuable diagnostic for ion spectra fundamental research and study the mass to charge composition of plasma with wide range of parameters

Proton Transfer Time-of-Flight Mass Spectrometer

Energy Technology Data Exchange (ETDEWEB)

Watson, Thomas B. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2016-03-01

The Proton Transfer Reaction Mass Spectrometer (PTRMS) measures gas-phase compounds in ambient air and headspace samples before using chemical ionization to produce positively charged molecules, which are detected with a time-of-flight (TOF) mass spectrometer. This ionization method uses a gentle proton transfer reaction method between the molecule of interest and protonated water, or hydronium ion (H₃O⁺), to produce limited fragmentation of the parent molecule. The ions produced are primarily positively charged with the mass of the parent ion, plus an additional proton. Ion concentration is determined by adding the number of ions counted at the molecular ion’s mass-to-charge ratio to the number of air molecules in the reaction chamber, which can be identified according to the pressure levels in the reaction chamber. The PTRMS allows many volatile organic compounds in ambient air to be detected at levels from 10–100 parts per trillion by volume (pptv). The response time is 1 to 10 seconds.

Avalanche photodiode based time-of-flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Ogasawara, Keiichi, E-mail: kogasawara@swri.edu; Livi, Stefano A.; Desai, Mihir I.; Ebert, Robert W.; McComas, David J.; Walther, Brandon C. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas 78238 (United States)

2015-08-15

This study reports on the performance of Avalanche Photodiodes (APDs) as a timing detector for ion Time-of-Flight (TOF) mass spectroscopy. We found that the fast signal carrier speed in a reach-through type APD enables an extremely short timescale response with a mass or energy independent <2 ns rise time for <200 keV ions (1−40 AMU) under proper bias voltage operations. When combined with a microchannel plate to detect start electron signals from an ultra-thin carbon foil, the APD comprises a novel TOF system that successfully operates with a <0.8 ns intrinsic timing resolution even using commercial off-the-shelf constant-fraction discriminators. By replacing conventional total-energy detectors in the TOF-Energy system, APDs offer significant power and mass savings or an anti-coincidence background rejection capability in future space instrumentation.

High-throughput shotgun lipidomics by quadrupole time-of-flight mass spectrometry

DEFF Research Database (Denmark)

Ståhlman, Marcus; Ejsing, Christer S.; Tarasov, Kirill

2009-01-01

Technological advances in mass spectrometry and meticulous method development have produced several shotgun lipidomic approaches capable of characterizing lipid species by direct analysis of total lipid extracts. Shotgun lipidomics by hybrid quadrupole time-of-flight mass spectrometry allows...... the absolute quantification of hundreds of molecular glycerophospholipid species, glycerolipid species, sphingolipid species and sterol lipids. Future applications in clinical cohort studies demand detailed lipid molecule information and the application of high-throughput lipidomics platforms. In this review...... we describe a novel high-throughput shotgun lipidomic platform based on 96-well robot-assisted lipid extraction, automated sample infusion by mircofluidic-based nanoelectrospray ionization, and quantitative multiple precursor ion scanning analysis on a quadrupole time-of-flight mass spectrometer...

Design of the multi-reflection time-of-flight mass spectrometer for the RAON facility

International Nuclear Information System (INIS)

Yoon, J.W.; Park, Y.H.; Park, S.J.; Kim, G.D.; Kim, Y.K.

2014-01-01

A multi-reflection time-of-flight mass spectrometer (MR-TOF-MS) has been proposed for high precision mass measurements on the future Korean heavy ion accelerator called RAON. MR-TOF-MS will allow us to reach very high mass resolving power (> 10 5 ) with extremely short measurement times (several ms) in a compact device. The MR-TOF-MS is composed of two electrostatic ion mirrors in combination with einzel lenses. The principle is that the injected ions travel for hundreds of revolutions inside MR-TOF-MS and ions with different masses are temporally separated. When temporal separation becomes larger than the ion bunch width, ions are extracted from the MR-TOF-MS by switching off the mirror voltages, and then arrive at a detector plane located at time focus, where an MCP detector for the mass measurement or an ion gate for the isobar separation is deployed. In this paper, simulation results for the MR-TOF-MS design using SIMION code are presented. Temporal broadenings, caused by the kinetic energy spread and the transverse emittance, were minimized by optimization of the electrode potentials, and it was demonstrated that the mass resolving power of 10 5 is achievable for the condition of an energy spread of ±30 eV and an emittance of 0.75 π*mm*mrad

Dustbuster: a New Generation Impact-ionization Time-of-flight Mass Spectrometer for in situ Analysis of Cosmic Dust

Science.gov (United States)

Austin, D. E.; Ahrens, T. J.; Beauchamp, J. L.

2000-10-01

We have developed and tested a small impact-ionization time-of-flight mass spectrometer for analysis of cosmic dust, suitable for use on deep space missions. This mass spectrometer, named Dustbuster, incorporates a large target area and a reflectron, simultaneously optimizing mass resolution, sensitivity, and collection efficiency. Dust particles hitting the 65-cm2 target plate are partially ionized. The resulting ions are accelerated through a modified reflectron that focuses the ions in space and time to produce high-resolution spectra. The instrument, shown below, measures 10 x 10 x 20 cm, has a mass of 500 g, and consumes little power. Laser desorption ionization of metal and mineral samples (embedded in the impact plate) simulates particle impacts for instrument performance tests. Mass resolution in these experiments is near 200, permitting resolution of isotopes. The mass spectrometer can be combined with other instrument components to determine dust particle trajectories and sizes. This project was funded by NASA's Planetary Instrument Definition and Development Program.

Pseudo-random neutron time-of-flight spectroscopy using a Van de Graaff accelerator as neutron source

International Nuclear Information System (INIS)

Duquesne, Henry; Schmitt, Andre; Poussot, Rene; Pelicier, Henri.

1976-05-01

The classical experiments of neutron time-of-flight spectrometry on bulk multiplying media are using recurrent neutron bursts from a linear accelerator. The adaptation of the ion beam issued from the Cadarache Van de Graaff accelerator is described with the test experiments which were effected. Both methods are compared with respect to the accuracy obtained, the energy resolution and the time consumed [fr

Ion optics of a time-of-flight mass spectrometer with electrostatic sector analyzers

International Nuclear Information System (INIS)

Sakurai, T.; Ito, H.; Matsuo, T.

1995-01-01

The ion optics for a high resolution time-of-flight mass spectrometer with electrostatic sector analyzers have been investigated. The multiple focusing (triple isochronous focusing and triple spacial focusing) conditions can be achieved by using a symmetrical arrangement of the sectors in a mass spectrometer. Both high mass resolution and high ion transmission can be accomplished simultaneously. The principles of MS/MS and MS/MS/MS analyses using a TOF mass spectrometer with electrostatic sector analyzers have been proposed. Product ion spectra can be obtained by measuring the total flight times and the kinetic energy of the products without any additional separation processes, any coincidence techniques or any special timing circuits. In an experiment, MS/MS and MS/MS/MS mass spectra have been obtained. The first generation product ions have been produced by a metastable decay, and the second generation products have been produced by a sequential decay. (orig.)

Multi-Reflection Time-of-Flight Mass Separation and Spectrometry

CERN Document Server

Kreim, Susanne; Wolf, R N

2014-01-01

The mass of a nucleus is one of its most fundamental ground-state properties and reveals the strength of nuclear binding. Investigating the binding energy of nuclei with respect to the number of protons and neutrons in a nucleus is important for advancing nuclear theory and increases our understanding of nucleosynthesis in supernovae and neutron stars. Precision mass measurements on radioactive nuclides belong to the state-of-the-art techniques [1, 2]. Presently, four complementary techniques are applied: isochronous and Schottky mass spectrometry in storage rings (IMS and SMS, respectively), magnetic-rigidity time-of-flight (TOF-ρ) measurements, and Penning-trap mass spectrometry (PTMS). With measurement cycles in the sub-ms range, IMS and TOF-Bρ MS are well suited for very short-lived species while offering moderate relative precision on the level of 10−6. A higher precision is achieved by SMS but with the need for measurement times on the order of several seconds. As soon as masses with a relative prec...

Mass cytometry: technique for real time single cell multitarget immunoassay based on inductively coupled plasma time-of-flight mass spectrometry.

Science.gov (United States)

Bandura, Dmitry R; Baranov, Vladimir I; Ornatsky, Olga I; Antonov, Alexei; Kinach, Robert; Lou, Xudong; Pavlov, Serguei; Vorobiev, Sergey; Dick, John E; Tanner, Scott D

2009-08-15

A novel instrument for real time analysis of individual biological cells or other microparticles is described. The instrument is based on inductively coupled plasma time-of-flight mass spectrometry and comprises a three-aperture plasma-vacuum interface, a dc quadrupole turning optics for decoupling ions from neutral components, an rf quadrupole ion guide discriminating against low-mass dominant plasma ions, a point-to-parallel focusing dc quadrupole doublet, an orthogonal acceleration reflectron analyzer, a discrete dynode fast ion detector, and an 8-bit 1 GHz digitizer. A high spectrum generation frequency of 76.8 kHz provides capability for collecting multiple spectra from each particle-induced transient ion cloud, typically of 200-300 micros duration. It is shown that the transients can be resolved and characterized individually at a peak frequency of 1100 particles per second. Design considerations and optimization data are presented. The figures of merit of the instrument are measured under standard inductively coupled plasma (ICP) operating conditions ( 900 for m/z = 159, the sensitivity with a standard sample introduction system of >1.4 x 10(8) ion counts per second per mg L(-1) of Tb and an abundance sensitivity of (6 x 10(-4))-(1.4 x 10(-3)) (trailing and leading masses, respectively) are shown. The mass range (m/z = 125-215) and abundance sensitivity are sufficient for elemental immunoassay with up to 60 distinct available elemental tags. When 500) can be used, which provides >2.4 x 10(8) cps per mg L(-1) of Tb, at (1.5 x 10(-3))-(5.0 x 10(-3)) abundance sensitivity. The real-time simultaneous detection of multiple isotopes from individual 1.8 microm polystyrene beads labeled with lanthanides is shown. A real time single cell 20 antigen expression assay of model cell lines and leukemia patient samples immuno-labeled with lanthanide-tagged antibodies is presented.

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)

A mechanical nanomembrane detector for time-of-flight mass spectrometry.

Science.gov (United States)

Park, Jonghoo; Qin, Hua; Scalf, Mark; Hilger, Ryan T; Westphall, Michael S; Smith, Lloyd M; Blick, Robert H

2011-09-14

We describe here a new principle for ion detection in time-of-flight (TOF) mass spectrometry in which an impinging ion packet excites mechanical vibrations in a silicon nitride (Si(3)N(4)) nanomembrane. The nanomembrane oscillations are detected by means of time-varying field emission of electrons from the mechanically oscillating nanomembrane. Ion detection is demonstrated in the MALDI-TOF analysis of proteins varying in mass from 5729 (insulin) to 150,000 (Immunoglobulin G) daltons. The detector response agrees well with the predictions of a thermomechanical model in which the impinging ion packet causes a nonuniform temperature distribution in the nanomembrane, exciting both fundamental and higher order oscillations.

Energy calibration of a 5. 5 MV Van de Graaff accelerator using a time-of-flight technique

Energy Technology Data Exchange (ETDEWEB)

Andrade, E.; Feregrino, M.; Zavala, E.P.; Pineda, J.C.; Jimenez, R.; Jaidar, A. (Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Fisica (Mexico))

1990-02-01

Energy calibration of the analysing magnet for the University of Mexico 5.5 MV Van de Graaff accelerator has been carried out using a time-of-flight method. The pulsed and bunched beam produced by the accelerator was used to deduce the energy E of the beam particles from the transit time between a coaxial pickup and a charged particle detector separated by 1.5 m. The measured FWHM energy resolution of this system was about 20 keV. (orig.).

Energy calibration of a 5.5 MV Van de Graaff accelerator using a time-of-flight technique

Science.gov (United States)

Andrade, E.; Feregrino, M.; Zavala, E. P.; Pineda, J. C.; Jiménez, R.; Jaidar, A.

1990-02-01

Energy calibration of the analysing magnet for the University of México 5.5 MV Van de Graaff accelerator has been carried out using a time-of-flight method. The pulsed and bunched beam produced by the accelerator was used to deduce the energy E of the beam particles from the transit time between a coaxial pickup and a charged particle detector separated by 1.5 m. The measured FWHM energy resolution of this system was about 20 keV.

Double-arm time-of-flight mass-spectrometer of nuclear fragments

International Nuclear Information System (INIS)

Ajvazian, G.M.; Astabatyan, R.A.

1995-01-01

A double-arm time-of-flight spectrometer of nuclear fragments for the investigation of heavy nuclei photofission in the intermediate energy range is described. The calibration results and working characteristics of the spectrometer, obtained using 252 Cf as a source of spontaneous fission, are presented. A mass resolution of σ m ∼2-3 a.m.u. was obtained within the registered fragments mass range of 80-160 a.m.u. The spectrometer was tested in the experiment on the investigation of 238 U nuclei fission by Bremsstahlung photons with Eγ max=1.75 GeV

Calibration of matrix-assisted laser desorption/ionization time-of-flight peptide mass fingerprinting spectra

DEFF Research Database (Denmark)

Hjernø, Karin; Højrup, Peter

2007-01-01

This chapter describes a number of aspects important for calibration of matrix-assisted laser desorption/ionization time-of-flight spectra prior to peptide mass fingerprinting searches. Both multipoint internal calibration and mass defect-based calibration is illustrated. The chapter describes ho...

Laser desorption and time-of-flight mass spectrometry. Fundamentals .Applications; Desorption laser et spectrometrie de masse par temps de vol. Aspects fondamentaux. Applications

Energy Technology Data Exchange (ETDEWEB)

Chaurand, P

1994-11-01

Time-of-flight mass spectrometry is a very powerful technique for the analysis of heavy molecular ions (100 000 u and more). The ejection in the gas phase and the ionization of these molecules is now possible through the MALDI technique (Matrix Assisted Laser Desorption Ionization). This technique consists in mixing the heavy molecules to be analysed with a organic matrix which absorbs at the wavelength of the laser. The necessary irradiance are of the order of 10{sup 6} W/cm{sup 2}. In these conditions we have shown that the mass resolutions are optimum and that the relative mass accuracies are of the order of 10{sup -4}. We have also demonstrated that the emission angle of the molecular ions in MALDI depends on the incident angle of the laser light. During the desorption process, the molecular ions are emitted in the opposite direction of the incident laser light. This effect is particularly important for the design of the accelerating stage of the time-of-flight spectrometers. Problems relative to the detection of these heavy molecular ions have been studied in details between 0.5 10{sup 4} m/s and 10{sup 5} m/s. The velocity threshold of the electronic emission is lower than the value of 0.5 10{sup 4} m/s. The relation between the electronic emission and the projectile velocity is complex. Finally, examples on mass identification of C{sub 60} molecules and derivated C{sub 60} are presented. Desorption methods are compared. (author). 32 refs., 34 figs.

Electrostatic mirror of time-of-flight focusing of charged particles and its application to mass spectrometry

International Nuclear Information System (INIS)

Berger, C.

1985-01-01

This invention is more particularly aimed at the electrostatic devices used in time-of-flight mass spectrometers. To obtain a better resolution and a maximum transmission, the mirror is characterized by three annular electrodes with same radius R: - having at least an inner conductor surface related to an electric source, - delimiting by their facing ends cross-sections, - spaced successively with coaxial arrangement, - having an axial length for the center electrode equal to 0,9 R and for the end electrodes a length enough to give to them a behaviour equivalent to a infinite length tube cylinder. Ion beams are reflected by the mirror which in the same time realizes the time-of-flight unicity for ion. TOF unicity means that time of flight will be the same for equal mass ions [fr

Absolute calibration of a time-of-flight spectrometer and imaging plate for the characterization of laser-accelerated protons

International Nuclear Information System (INIS)

Choi, I W; Kim, C M; Sung, J H; Kim, I J; Yu, T J; Lee, S K; Jin, Y-Y; Pae, K H; Hafz, N; Lee, J

2009-01-01

A proton energy spectrometer system is composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), and is used to characterize laser-accelerated protons. The TOFS detects protons with a plastic scintillator, and the TPS with a CR-39 or imaging plate (IP). The two spectrometers can operate simultaneously and give separate time-of-flight (TOF) and Thomson parabola (TP) data. We propose a method to calibrate the TOFS and IP by comparing the TOF data and the TP data taken with CR-39 and IP. The absolute response of the TOFS as a function of proton energy is calculated from the proton number distribution measured with CR-39. The sensitivity of IP to protons is obtained from the proton number distribution estimated with the calibrated TOFS. This method, based on the comparison of the simultaneously measured data, gives more reliable results when using laser-accelerated protons as a calibration source. The calibrated spectrometer system can be used to measure absolutely calibrated energy spectra for the optimization of laser-accelerated protons

[Separation and identification of bovine lactoferricin by high performance liquid chromatography-matrix-assisted laser desorption/ionization time of flight/ time of flight mass spectrometry].

Science.gov (United States)

An, Meichen; Liu, Ning

2010-02-01

A high performance liquid chromatography-matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry (HPLC-MALDI-TOF/TOF MS) method was developed for the separation and identification of bovine lactoferricin (LfcinB). Bovine lactoferrin was hydrolyzed by pepsin and then separated by ion exchange chromatography and reversed-phase liquid chromatography (RP-LC). The antibacterial activities of the fractions from RP-LC separation were determined and the protein concentration of the fraction with the highest activity was measured, whose sequence was indentified by MALDI-TOF/TOF MS. The relative molecular mass of LfcinB was 3 124.89 and the protein concentration was 18.20 microg/mL. The method of producing LfcinB proposed in this study has fast speed, high accuracy and high resolution.

Development of a hand-portable photoionization time-of-flight mass spectrometer

International Nuclear Information System (INIS)

Dieckman, S.L.; Bostrom, G.A.; Waterfield, L.G.; Jendrzejczyk, J.A.; Raptis, A.C.

1996-01-01

ANL is currently developing a portable chemical sensor system based on laser desorption photoionization time-of-flight mass spectrometry. It will incorporate direct sampling, a cryocooler base sample adsorption and concentration, and direct surface multiphoton ionization. All components will be in a package 9 x 11 x 4 in., weighing 15-18 lbs. A sample spectrum is given for a NaCl sample

Miniature Time of Flight Mass Spectrometer for Space and Extraterrestrial Applications, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The PI has developed a miniature time-of-flight mass spectrometer (TOF-MS), which can be op-timized for space and extraterrestrial applications, by using a...

LVGEMS Time-of-Flight Mass Spectrometry on Satellites

Science.gov (United States)

Herrero, Federico

2013-01-01

NASA fs investigations of the upper atmosphere and ionosphere require measurements of composition of the neutral air and ions. NASA is able to undertake these observations, but the instruments currently in use have their limitations. NASA has extended the scope of its research in the atmosphere and now requires more measurements covering more of the atmosphere. Out of this need, NASA developed multipoint measurements using miniaturized satellites, also called nanosatellites (e.g., CubeSats), that require a new generation of spectrometers that can fit into a 4 4 in. (.10 10 cm) cross-section in the upgraded satellites. Overall, the new mass spectrometer required for the new depth of atmospheric research must fulfill a new level of low-voltage/low-power requirements, smaller size, and less risk of magnetic contamination. The Low-Voltage Gated Electrostatic Mass Spectrometer (LVGEMS) was developed to fulfill these requirements. The LVGEMS offers a new spectrometer that eliminates magnetic field issues associated with magnetic sector mass spectrometers, reduces power, and is about 1/10 the size of previous instruments. LVGEMS employs the time of flight (TOF) technique in the GEMS mass spectrometer previously developed. However, like any TOF mass spectrometer, GEMS requires a rectangular waveform of large voltage amplitude, exceeding 100 V -- that means that the voltage applied to one of the GEMS electrodes has to change from 0 to 100 V in a time of only a few nanoseconds. Such electronic speed requires more power than can be provided in a CubeSat. In the LVGEMS, the amplitude of the rectangular waveform is reduced to about 1 V, compatible with digital electronics supplies and requiring little power.

First Direct Mass Measurements of Nuclides around Z =100 with a Multireflection Time-of-Flight Mass Spectrograph

Science.gov (United States)

Ito, Y.; Schury, P.; Wada, M.; Arai, F.; Haba, H.; Hirayama, Y.; Ishizawa, S.; Kaji, D.; Kimura, S.; Koura, H.; MacCormick, M.; Miyatake, H.; Moon, J. Y.; Morimoto, K.; Morita, K.; Mukai, M.; Murray, I.; Niwase, T.; Okada, K.; Ozawa, A.; Rosenbusch, M.; Takamine, A.; Tanaka, T.; Watanabe, Y. X.; Wollnik, H.; Yamaki, S.

2018-04-01

The masses of 246Es, 251Fm, and the transfermium nuclei Md-252249 and 254No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N =152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of 246Es and 249,250,252Md were measured for the first time. Using the masses of Md,250249 as anchor points for α decay chains, the masses of heavier nuclei, up to 261Bh and 266Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ2 n derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N =152 neutron shell closure for Md and Lr.

Fully automatic and precise data analysis developed for time-of-flight mass spectrometry.

Science.gov (United States)

Meyer, Stefan; Riedo, Andreas; Neuland, Maike B; Tulej, Marek; Wurz, Peter

2017-09-01

Scientific objectives of current and future space missions are focused on the investigation of the origin and evolution of the solar system with the particular emphasis on habitability and signatures of past and present life. For in situ measurements of the chemical composition of solid samples on planetary surfaces, the neutral atmospheric gas and the thermal plasma of planetary atmospheres, the application of mass spectrometers making use of time-of-flight mass analysers is a technique widely used. However, such investigations imply measurements with good statistics and, thus, a large amount of data to be analysed. Therefore, faster and especially robust automated data analysis with enhanced accuracy is required. In this contribution, an automatic data analysis software, which allows fast and precise quantitative data analysis of time-of-flight mass spectrometric data, is presented and discussed in detail. A crucial part of this software is a robust and fast peak finding algorithm with a consecutive numerical integration method allowing precise data analysis. We tested our analysis software with data from different time-of-flight mass spectrometers and different measurement campaigns thereof. The quantitative analysis of isotopes, using automatic data analysis, yields results with an accuracy of isotope ratios up to 100 ppm for a signal-to-noise ratio (SNR) of 10 4 . We show that the accuracy of isotope ratios is in fact proportional to SNR -1 . Furthermore, we observe that the accuracy of isotope ratios is inversely proportional to the mass resolution. Additionally, we show that the accuracy of isotope ratios is depending on the sample width T s by T s 0.5 . Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Multiple-reflection time-of-flight mass spectrometry for in situ applications

Science.gov (United States)

Dickel, T.; Plaß, W. R.; Lang, J.; Ebert, J.; Geissel, H.; Haettner, E.; Jesch, C.; Lippert, W.; Petrick, M.; Scheidenberger, C.; Yavor, M. I.

2013-12-01

Multiple-reflection time-of-flight mass spectrometers (MR-TOF-MS) have recently been installed at different low-energy radioactive ion beam facilities. They are used as isobar separators with high ion capacity and as mass spectrometers with high mass resolving power and accuracy for short-lived nuclei. Furthermore, MR-TOF-MS have a huge potential for applications in other fields, such as chemistry, biology, medicine, space science, and homeland security. The development, commissioning and results of an MR-TOF-MS is presented, which serves as proof-of-principle to show that very high mass resolving powers (∼105) can be achieved in a compact device (length ∼30 cm). Based on this work, an MR-TOF-MS for in situ application has been designed. For the first time, this device combines very high mass resolving power (>105), mobility, and an atmospheric pressure inlet in one instrument. It will enable in situ measurements without sample preparation at very high mass accuracy. Envisaged applications of this mobile MR-TOF-MS are discussed.

Identification of microorganisms using superconducting tunnel junctions and time-of-flight mass spectrometry

Science.gov (United States)

Ullom, J. N.; Frank, M.; Horn, J. M.; Labov, S. E.; Langry, K.; Benner, W. H.

2000-04-01

We present time-of-flight measurements of biological material ejected from bacterial spores following laser irradiation. Ion impacts are registered on a microchannel plate detector and on a Superconducting Tunnel Junction (STJ) detector. We compare mass spectra obtained with the two detectors. The STJ has better sensitivity to massive ions and also measures the energy of each ion. We show evidence that spores of different bacillus species produce distinctive mass spectra and associate the observed mass peaks with coat proteins.

Identification of microorganisms using superconducting tunnel junctions and time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Ullom, J.N.; Frank, M.; Horn, J.M.; Labov, S.E.; Langry, K.; Benner, W.H.

2000-01-01

We present time-of-flight measurements of biological material ejected from bacterial spores following laser irradiation. Ion impacts are registered on a microchannel plate detector and on a Superconducting Tunnel Junction (STJ) detector. We compare mass spectra obtained with the two detectors. The STJ has better sensitivity to massive ions and also measures the energy of each ion. We show evidence that spores of different bacillus species produce distinctive mass spectra and associate the observed mass peaks with coat proteins

Physical design of time-of-flight mass spectrometer in energetic cluster impact deposition apparatus

International Nuclear Information System (INIS)

Yu Guoqing; Shi Ying; Chen Jingsheng; Zhu Dezhang; Pan Haochang; Xu Hongjie

1999-01-01

The principle and physical design of the time-of-flight mass spectrometer equipped in the energetic cluster impact deposition apparatus are introduced. Some problems existed in experiments and their solutions are also discussed

The mass spectral density in quantitative time-of-flight mass spectrometry of polymers

Science.gov (United States)

Tate, Ranjeet S.; Ebeling, Dan; Smith, Lloyd M.

2001-03-01

Time-of-flight mass spectrometry (TOF-MS) is being increasingly used for the study of polymers, for example to obtain the distribution of molecular masses for polymer samples. Serious efforts have also been underway to use TOF-MS for DNA sequencing. In TOF-MS the data is obtained in the form of a time-series that represents the distribution in arrival times of ions of various m/z ratios. This time-series data is then converted to a "mass-spectrum" via a coordinate transformation from the arrival time (t) to the corresponding mass-to-charge ratio (m/z = const. t^2). In this transformation, it is important to keep in mind that spectra are distributions, or densities of weight +1, and thus do not transform as functions. To obtain the mass-spectral density, it is necessary to include a multiplicative factor of √m/z. Common commercial instruments do not take this factor into account. Dropping this factor has no effect on qualitative analysis (detection) or local quantitative measurements, since S/N or signal-to-baseline ratios are unaffected for peaks with small dispersions. However, there are serious consequences for general quantitative analyses. In DNA sequencing applications, loss of signal intensity is in part attributed to multiple charging; however, since the √m/z factor is not taken into account, this conclusion is based on an overestimate (by a factor of √z) of the relative amount of the multiply charged species. In the study of polymers, the normalized dispersion is underestimated by approximately (M_w/Mn -1)/2. In terms of M_w/Mn itself, for example, a M_w/M_n=1.5 calculated without the √m factor corresponds in fact to a M_w/M_n=1.88.

Plasma Desorption Mass Spectrometry using TANDEM accelerator in National Industrial Research Inst. of Nagoya

Energy Technology Data Exchange (ETDEWEB)

Mizota, Takeshi; Nakao, Setsuo; Niwa, Hiroaki; Saito, Kazuo [Particle Beam Sceince Laboratory, Multi-Function Material Science Department, National Industrial Research Inst. of Nagoya, Nagoya (Japan)

2001-02-01

Plasma Desorption Mass Spectrometry (PDMS) analysis was studied using TANDEM accelerator. The heavy ions of MeV range emit the secondary ions of atoms, molecules, polymers and clusters from the irradiated samples without destruction. The analysis system of PDMS designed and set-up using a mass spectrometer of Time of Flight and the TANDEM accelerator. The system performance was tested for C-60 fullerene on the surface of the samples using 11.2 MeV {sup 28}Si beams produced by the TANDEM accelerator of 1.7MV. The result shows that the hydrogen and hydrocarbons can be analyzed in the range of 1amu unit. The resolution (M/{delta}M) of the Mass Spectrometry system is confirmed to be about 1000 from the separation of the 720 and 721amu peaks, which is attributed to the C-60 fullerene including {sup 13}C atoms. (H. Katsuta)

Time of flight and range of the motion of a projectile in a constant gravitational field

Directory of Open Access Journals (Sweden)

P. A. Karkantzakos

2009-01-01

Full Text Available In this paper we study the classical problem of the motion of a projectile in a constant gravitational field under the influenceof a retarding force proportional to the velocity. Specifically, we express the time of flight, the time of fall and the range ofthe motion as a function of the constant of resistance per unit mass of the projectile. We also prove that the time of fall isgreater than the time of rise with the exception of the case of zero constant of resistance where we have equality. Finally weprove a formula from which we can compute the constant of resistance per unit mass of the projectile from time of flight andrange of the motion when the acceleration due to gravity and the initial velocity of the projectile are known.

Nuclear Forensics: Measurements of Uranium Oxides Using Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

Science.gov (United States)

2010-03-01

Isotope Ratio Analysis of Actinides , Fission Products, and Geolocators by High- efficiency Multi-collector Thermal Ionization Mass Spectrometry...Information, 1999. Hou, Xiaolin, and Per Roos. “ Critical Comparison of radiometric and Mass Spectrometric Methods for the Determination of...NUCLEAR FORENSICS: MEASUREMENTS OF URANIUM OXIDES USING TIME-OF-FLIGHT SECONDARY ION MASS

An electrostatic beam line for accelerator mass spectroscopy of exotic particles

International Nuclear Information System (INIS)

Elmore, D.; Kubik, P.W.; Hemmick, T.; Teng, R.; Kagan, H.; Haas, P.; Boyd, R.N.; Turner, R.; Nitz, D.; Ciampa, D.; Olsen, S.L.; Gentile, T.; Haelen, T.

1985-01-01

An all-electrostatic charged particle spectrometer has been constructed to perform high sensitivity searches for exotic states of matter. This spectrometer consists of an electrosatic beam line capable of mass independent charged particle transport and selection together with time-of-flight, energy loss and total energy detectors. This system has been used in conjunction with the tandem electrostatic accelerator at the Nuclear Structure Research Laboratory of the University of Rochester to search for fractionally charged or anomalously heavy particles. (orig.)

An improvement of isochronous mass spectrometry: Velocity measurements using two time-of-flight detectors

International Nuclear Information System (INIS)

Shuai, P.; Xu, X.; Zhang, Y.H.; Xu, H.S.; Litvinov, Yu. A.; Wang, M.

2016-01-01

Isochronous mass spectrometry (IMS) in storage rings is a powerful tool for mass measurements of exotic nuclei with very short half-lives down to several tens of microseconds, using a multicomponent secondary beam separated in-flight without cooling. However, the inevitable momentum spread of secondary ions limits the precision of nuclear masses determined by using IMS. Therefore, the momentum measurement in addition to the revolution period of stored ions is crucial to reduce the influence of the momentum spread on the standard deviation of the revolution period, which would lead to a much improved mass resolving power of IMS. One of the proposals to upgrade IMS is that the velocity of secondary ions could be directly measured by using two time-of-flight (double TOF) detectors installed in a straight section of a storage ring. In this paper, we outline the principle of IMS with double TOF detectors and the method to correct the momentum spread of stored ions.

High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

DEFF Research Database (Denmark)

Andersen, Thomas; Jensen, Robert; Christensen, M. K.

2012-01-01

We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal...

Time-of-flight mass spectrographs—From ions to neutral atoms

Science.gov (United States)

Möbius, E.; Galvin, A. B.; Kistler, L. M.; Kucharek, H.; Popecki, M. A.

2016-12-01

After their introduction to space physics in the mid 1980s time-of-flight (TOF) spectrographs have become a main staple in spaceborne mass spectrometry. They have largely replaced magnetic spectrometers, except when extremely high mass resolution is required to identify complex molecules, for example, in the vicinity of comets or in planetary atmospheres. In combination with electrostatic analyzers and often solid state detectors, TOF spectrographs have become key instruments to diagnose space plasma velocity distributions, mass, and ionic charge composition. With a variety of implementation schemes that also include isochronous electric field configurations, TOF spectrographs can respond to diverse science requirements. This includes a wide range in mass resolution to allow the separation of medium heavy isotopes or to simply provide distributions of the major species, such as H, He, and O, to obtain information on source tracers or mass fluxes. With a top-hat analyzer at the front end, or in combination with deflectors for three-axis stabilized spacecraft, the distribution function of ions can be obtained with good time resolution. Most recently, the reach of TOF ion mass spectrographs has been extended to include energetic neutral atoms. After selecting the arrival direction with mechanical collimation, followed by conversion to ions, adapted TOF sensors form a new branch of the spectrograph family tree. We review the requirements, challenges, and implementation schemes for ion and neutral atom spectrographs, including potential directions for the future, while largely avoiding overlap with complementary contributions in this special issue.

A novel ion cooling trap for multi-reflection time-of-flight mass spectrograph

Energy Technology Data Exchange (ETDEWEB)

Ito, Y., E-mail: yito@riken.jp [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Schury, P. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States); Wada, M.; Naimi, S. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Smorra, C. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Sonoda, T. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mita, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Takamine, A. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Aoyama Gakuin University, 4-4-25 Shibuya, Shibuya-ku, Tokyo 150-8366 (Japan); Okada, K. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Sophia University, 7-1 Kioi-cho, Chiyoda-ku, Tokyo 102-8554 (Japan); Ozawa, A. [University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Wollnik, H. [SLOWRI Team, Nishina Accelerator-Based Research Center, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); New Mexico State University, Department Chemistry and Biochemistry, Las Cruces, NM 88003 (United States)

2013-12-15

Highlights: • Fast cooling time: 2 ms. • High efficiency: ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +}. • 100% Duty cycle with double trap system. -- Abstract: A radiofrequency quadrupole ion trap system for use with a multi-reflection time-of-flight mass spectrograph (MRTOF) for short-lived nuclei has been developed. The trap system consists of two different parts, an asymmetric taper trap and a flat trap. The ions are cooled to a sufficient small bunch for precise mass measurement with MRTOF in only 2 ms cooling time in the flat trap, then orthogonally ejected to the MRTOF for mass analysis. A trapping efficiency of ≈27% for {sup 23}Na{sup +} and ≈5.1% for {sup 7}Li{sup +} has been achieved.

Multiple-reflection time-of-flight mass spectrometry for in situ applications

International Nuclear Information System (INIS)

Dickel, T.; Plaß, W.R.; Lang, J.; Ebert, J.; Geissel, H.; Haettner, E.; Jesch, C.; Lippert, W.; Petrick, M.; Scheidenberger, C.; Yavor, M.I.

2013-01-01

Highlights: • MR-TOF-MS: huge potential in chemistry, medicine, space science, homeland security. • Compact MR-TOF-MS (length ∼30 cm) with very high mass resolving powers (10 5 ). • Combination of high resolving power (>10 5 ), mobility, API for in situ measurements. • Envisaged applications of mobile MR-TOF-MS. -- Abstract: Multiple-reflection time-of-flight mass spectrometers (MR-TOF-MS) have recently been installed at different low-energy radioactive ion beam facilities. They are used as isobar separators with high ion capacity and as mass spectrometers with high mass resolving power and accuracy for short-lived nuclei. Furthermore, MR-TOF-MS have a huge potential for applications in other fields, such as chemistry, biology, medicine, space science, and homeland security. The development, commissioning and results of an MR-TOF-MS is presented, which serves as proof-of-principle to show that very high mass resolving powers (∼10 5 ) can be achieved in a compact device (length ∼30 cm). Based on this work, an MR-TOF-MS for in situ application has been designed. For the first time, this device combines very high mass resolving power (>10 5 ), mobility, and an atmospheric pressure inlet in one instrument. It will enable in situ measurements without sample preparation at very high mass accuracy. Envisaged applications of this mobile MR-TOF-MS are discussed

Multiple-reflection time-of-flight mass spectrometry for in situ applications

Energy Technology Data Exchange (ETDEWEB)

Dickel, T., E-mail: t.dickel@gsi.de [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Plaß, W.R. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Lang, J.; Ebert, J. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Geissel, H.; Haettner, E. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Jesch, C.; Lippert, W.; Petrick, M. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); Scheidenberger, C. [II. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt (Germany); Yavor, M.I. [Institute for Analytical Instrumentation, Russian Academy of Sciences, 190103 St. Petersburg (Russian Federation)

2013-12-15

Highlights: • MR-TOF-MS: huge potential in chemistry, medicine, space science, homeland security. • Compact MR-TOF-MS (length ∼30 cm) with very high mass resolving powers (10{sup 5}). • Combination of high resolving power (>10{sup 5}), mobility, API for in situ measurements. • Envisaged applications of mobile MR-TOF-MS. -- Abstract: Multiple-reflection time-of-flight mass spectrometers (MR-TOF-MS) have recently been installed at different low-energy radioactive ion beam facilities. They are used as isobar separators with high ion capacity and as mass spectrometers with high mass resolving power and accuracy for short-lived nuclei. Furthermore, MR-TOF-MS have a huge potential for applications in other fields, such as chemistry, biology, medicine, space science, and homeland security. The development, commissioning and results of an MR-TOF-MS is presented, which serves as proof-of-principle to show that very high mass resolving powers (∼10{sup 5}) can be achieved in a compact device (length ∼30 cm). Based on this work, an MR-TOF-MS for in situ application has been designed. For the first time, this device combines very high mass resolving power (>10{sup 5}), mobility, and an atmospheric pressure inlet in one instrument. It will enable in situ measurements without sample preparation at very high mass accuracy. Envisaged applications of this mobile MR-TOF-MS are discussed.

Real time monitoring of accelerated chemical reactions by ultrasonication-assisted spray ionization mass spectrometry.

Science.gov (United States)

Lin, Shu-Hsuan; Lo, Ta-Ju; Kuo, Fang-Yin; Chen, Yu-Chie

2014-01-01

Ultrasonication has been used to accelerate chemical reactions. It would be ideal if ultrasonication-assisted chemical reactions could be monitored by suitable detection tools such as mass spectrometry in real time. It would be helpful to clarify reaction intermediates/products and to have a better understanding of reaction mechanism. In this work, we developed a system for ultrasonication-assisted spray ionization mass spectrometry (UASI-MS) with an ~1.7 MHz ultrasonic transducer to monitor chemical reactions in real time. We demonstrated that simply depositing a sample solution on the MHz-based ultrasonic transducer, which was placed in front of the orifice of a mass spectrometer, the analyte signals can be readily detected by the mass spectrometer. Singly and multiply charged ions from small and large molecules, respectively, can be observed in the UASI mass spectra. Furthermore, the ultrasonic transducer used in the UASI setup accelerates the chemical reactions while being monitored via UASI-MS. The feasibility of using this approach for real-time acceleration/monitoring of chemical reactions was demonstrated. The reactions of Girard T reagent and hydroxylamine with steroids were used as the model reactions. Upon the deposition of reactant solutions on the ultrasonic transducer, the intermediate/product ions are readily generated and instantaneously monitored using MS within 1 s. Additionally, we also showed the possibility of using this reactive UASI-MS approach to assist the confirmation of trace steroids from complex urine samples by monitoring the generation of the product ions. Copyright © 2014 John Wiley & Sons, Ltd.

A high performance Time-of-Flight detector applied to isochronous mass measurement at CSRe

International Nuclear Information System (INIS)

Mei Bo; Tu Xiaolin; Wang Meng; Xu Hushan; Mao Ruishi; Hu Zhengguo; Ma Xinwen; Yuan Youjin; Zhang Xueying; Geng Peng; Shuai Peng; Zang Yongdong; Tang Shuwen; Ma Peng; Lu Wan; Yan Xinshuai; Xia Jiawen; Xiao Guoqing; Guo Zhongyan; Zhang Hongbin

2010-01-01

A high performance Time-of-Flight detector has been designed and constructed for isochronous mass spectrometry at the experimental Cooler Storage Ring (CSRe). The detector has been successfully used in an experiment to measure the masses of the N∼Z∼33 nuclides near the proton drip-line. Of particular interest is the mass of 65 As. A maximum detection efficiency of 70% and a time resolution of 118±8 ps (FWHM) have been achieved in the experiment. The dependence of detection efficiency and signal average pulse height (APH) on atomic number Z has been studied. The potential of APH for Z identification has been discussed.

Position sensitive detection coupled to high-resolution time-of-flight mass spectrometry: Imaging for molecular beam deflection experiments

International Nuclear Information System (INIS)

Abd El Rahim, M.; Antoine, R.; Arnaud, L.; Barbaire, M.; Broyer, M.; Clavier, Ch.; Compagnon, I.; Dugourd, Ph.; Maurelli, J.; Rayane, D.

2004-01-01

We have developed and tested a high-resolution time-of-flight mass spectrometer coupled to a position sensitive detector for molecular beam deflection experiments. The major achievement of this new spectrometer is to provide a three-dimensional imaging (X and Y positions and time-of-flight) of the ion packet on the detector, with a high acquisition rate and a high resolution on both the mass and the position. The calibration of the experimental setup and its application to molecular beam deflection experiments are discussed

A small sized time-of-flight mass spectrometer for simultaneous measurement of neutral and ionic species effusing from plasma, 1

International Nuclear Information System (INIS)

Horiuchi, Yukihiko

1986-01-01

A principle for simultaneous and real time measurement of neutral and ionic species effusing from plasma by using a time-of-flight mass spectrometer is proposed. A simple, small sized time-of-flight mass spectrometer combined with a dc glow discharge tube and an ion sampling electrode system for the simultaneous measurement on the basis of the proposed plinciple, has been constructed and tested. Details of the experimental setup including the geometry and the electronic hardware are described. It is shown that mass spectra of neutrals and ions from the positive column of the argon dc glow discharge are successfully observed on a single oscilloscope display. (author)

ALICE Time of Flight Module

CERN Multimedia

The Time-Of-Flight system of ALICE consists of 90 such modules, each containing 15 or 19 Multigap Resistive Plate Chamber (MRPC) strips. This detector is used for identification of charged particles. It measures with high precision (50 ps) the time of flight of charged particles and therefore their velocity. The curvature of the particle trajectory inside the magnetic field gives the momentum, thus the particle mass is calculated and the particle is identified The MRPC is a stack of resistive glass plates, separated from each other by nylon fishing line. The mass production of the chambers (~1600, covering a surface of 150 m2) was done at INFN Bologna, while the first prototypes were bult at CERN.

TOF plotter - a program to perform routine analysis time-of-flight mass spectral data

International Nuclear Information System (INIS)

Knippel, Brad C.; Padgett, Clifford W.; Marcus, R. Kenneth

2004-01-01

The main article discusses the operation and application of the program to mass spectral data files. This laboratory has recently reported the construction and characterization of a linear time-of-flight mass spectrometer (ToF-MS) utilizing a radio frequency glow discharge ionization source. Data acquisition and analysis was performed using a digital oscilloscope and Microsoft Excel, respectively. Presently, no software package is available that is specifically designed for time-of-flight mass spectral analysis that is not instrument dependent. While spreadsheet applications such as Excel offer tremendous utility, they can be cumbersome when repeatedly performing tasks which are too complex or too user intensive for macros to be viable. To address this situation and make data analysis a faster, simpler task, our laboratory has developed a Microsoft Windows-based software program coded in Microsoft Visual Basic. This program enables the user to rapidly perform routine data analysis tasks such as mass calibration, plotting and smoothing on x-y data sets. In addition to a suite of tools for data analysis, a number of calculators are built into the software to simplify routine calculations pertaining to linear ToF-MS. These include mass resolution, ion kinetic energy and single peak identification calculators. A detailed description of the software and its associated functions is presented followed by a characterization of its performance in the analysis of several representative ToF-MS spectra obtained from different GD-ToF-MS systems

Tandem Mass Spectrometry on a Miniaturized Laser Desorption Time-of-Flight Mass Spectrometer

Science.gov (United States)

Li, Xiang; Cornish, Timothy; Getty, Stephanie A.; Brinckerhoff, William B.

2016-01-01

Tandem mass spectrometry (MSMS) is a powerful and widely-used technique for identifying the molecular structure of organic constituents of a complex sample. Application of MSMS to the study of unknown planetary samples on a remote space mission would contribute to our understanding of the origin, evolution, and distribution of extraterrestrial organics in our solar system. Here we report on the realization of MSMS on a miniaturized laser desorption time-of-flight mass spectrometer (LD-TOF-MS), which is one of the most promising instrument types for future planetary missions. This achievement relies on two critical components: a curved-field reflectron and a pulsed-pin ion gate. These enable use of the complementary post-source decay (PSD) and laser-assisted collision induced dissociation (L-CID) MSMS methods on diverse measurement targets with only modest investment in instrument resources such as volume and weight. MSMS spectra of selected molecular targets in various organic standards exhibit excellent agreement when compared with results from a commercial, laboratory-scale TOF instrument, demonstrating the potential of this powerful technique in space and planetary environments.

An Improvement on Space Focusing Resolution in Two-Field Time-of-Flight Mass Spectrometers

International Nuclear Information System (INIS)

Yildirim, M.; Aydin, R.; Akin, U.; Kilic, H. S.; Sise, O.; Ulu, M.; Dogan, M.

2007-01-01

Time-of-Flight Mass Spectrometer (TOFMS) is a sophisticated device for the mass selective analysis of a variety of samples. The main limitation on TOFMS technique is the obtainable resolution where the two main limiting factors are the initial space and energy spread of particles created in ionization region. Similar charged particles starting at different points will reach the detector at different times. So, this problem makes space focusing is very important subject. We have presented principles of two-fields TOFMS with second-order space focusing both using analytical methods and ray-tracing simulation. This work aims understanding of ion optical system clearly and gives hint of expectation for future developments

Dual cascade time-of-flight mass spectrometer basing on electrostatic mirrors with two dimensional fields

International Nuclear Information System (INIS)

Glikman, L. G.; Goloskokov, Yu. V.; Karetskaya, S.P.; Mit', A.G.

1999-01-01

In the report [1] we have suggested the scheme of time-of-flight spectrometer containing two electrostatic mirrors with two dimensional field that doesn't depend on one of the Cartesian coordinates). In the articles [2,3] there have been found conditions for obtaining high quality of time-of-flight and spatial focusing. One of basic advantages of this scheme - is availability of intermediate stigmatic image. In the plane where this image is it's possible to place controlled diaphragm that limits ion scatter along the energy if the scatter is too large. With the help of this diaphragm at the spectrometer you can register mass spectrum with the selected energy. Good focusing quality allows reducing of initial ion energy by this increasing the time of their flight and thus analyzers resolving ability. Ion source and receiver are spaced at rather a long distances. This can be useful to solve some practical tasks

Mass measurements of {sup 238}U-projectile fragments for the first time with a multiple-reflection time-of-flight mass spectrometer

Energy Technology Data Exchange (ETDEWEB)

Ebert, Jens

2016-07-01

Mass measurements of short-lived uranium projectile fragments were performed for the first time with a Multiple-Reflexion-Time-of-Flight Mass Spectrometer (MR-TOF-MS). A major part of this doctoral work was a novel development of a data analysis method for the MR-TOF-MS mass measurements of exotic nuclei at the fragment separator FRS at GSI. The developed method was successfully applied to the data obtained from two pilot experiments with the MR-TOF-MS at the FRS in 2012 and 2014. A substantial upgrade of the experimental setup of the MR-TOF-MS was also performed in the frame work of this doctoral thesis after the first run. In the experiments projectile fragments were created with 1000 MeV/u {sup 238}U ions in a Be/Nb target at the entrance of the in-flight separator FRS. The exotic nuclei were spatially separated, energy bunched and slowed down with the ion-optical system of the FRS combined with monoenergetic and homogeneous degraders. At the final focal plane of the FRS the fragments were completely slowed down and thermalized in a cryogenic stopping cell (CSC) filled with 3-5 mg/cm{sup 2} pure helium gas. The exotic nuclei were fast extracted from the CSC to enable mass measurements of very short-lived fragments with the MR-TOF-MS. The achievement of this goal was successfully demonstrated with the mass measurement of {sup 220}Ra ions with a half-life of 17.9 ms and 11 detected events. The mass measurements of the isobars {sup 211}Fr, {sup 211}Po and {sup 211}Rn have clearly demonstrated the scientific potential of the MR-TOF-MS for the investigation of exotic nuclei and the power of the data analysis system. Difficult measurements with overlapping mass distributions with only a few counts in the measured spectra were the challenge for the new data analysis method based on the maximum likelihood method. The drifts during the measurements were corrected with the developed time-resolved calibration method. After the improvements of the setup as a consequence of

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.

Invited Article: Characterization of background sources in space-based time-of-flight mass spectrometers

International Nuclear Information System (INIS)

Gilbert, J. A.; Gershman, D. J.; Gloeckler, G.; Lundgren, R. A.; Zurbuchen, T. H.; Orlando, T. M.; McLain, J.; Steiger, R. von

2014-01-01

For instruments that use time-of-flight techniques to measure space plasma, there are common sources of background signals that evidence themselves in the data. The background from these sources may increase the complexity of data analysis and reduce the signal-to-noise response of the instrument, thereby diminishing the science value or usefulness of the data. This paper reviews several sources of background commonly found in time-of-flight mass spectrometers and illustrates their effect in actual data using examples from ACE-SWICS and MESSENGER-FIPS. Sources include penetrating particles and radiation, UV photons, energy straggling and angular scattering, electron stimulated desorption of ions, ion-induced electron emission, accidental coincidence events, and noise signatures from instrument electronics. Data signatures of these sources are shown, as well as mitigation strategies and design considerations for future instruments

ALICE Time Of Flight Detector

CERN Multimedia

Alici, A

2013-01-01

Charged particles in the intermediate momentum range are identified in ALICE by the Time Of Flight (TOF) detector. The time measurement with the TOF, in conjunction with the momentum and track length measured by the tracking detector, is used to calculate the particle mass.

Gas chromatography interfaced with atmospheric pressure ionization-quadrupole time-of-flight-mass spectrometry by low-temperature plasma ionization

DEFF Research Database (Denmark)

Norgaard, Asger W.; Kofoed-Sorensen, Vivi; Svensmark, Bo

2013-01-01

A low temperature plasma (LTP) ionization interface between a gas chromatograph (GC) and an atmospheric pressure inlet mass spectrometer, was constructed. This enabled time-of-flight mass spectrometric detection of GC-eluting compounds. The performance of the setup was evaluated by injection...

Detection and quantification of neurotensin in human brain tissue by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

DEFF Research Database (Denmark)

Gobom, J; Kraeuter, K O; Persson, R

2000-01-01

A method was developed for mass spectrometric detection of neurotensin (NT)-like immunoreactivity and quantification of NT in human brain tissue. The method is based on immunoprecipitation followed by analysis using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF......-MS). The identity of the major component of the immunoprecipitates as neurotensin was confirmed by fragment ion analysis on an electrospray ionization quadrupole time-of-flight instrument. MALDI-TOF-MS quantification of NT was achieved using stable-isotope-labeled NT as the internal standard, yielding an error...

Control of Strobilurin Fungicides in Wheat Using Direct Analysis in Real Time Accurate Time-of-Flight and Desorption Electrospray Ionization Linear Ion Trap Mass Spectrometry

NARCIS (Netherlands)

Schurek, J.; Vaclavik, L.; Hooijerink, H.; Lacina, O.; Poustka, J.; Sharman, M.; Caldow, M.; Nielen, M.W.F.; Hajslova, J.

2008-01-01

Ambient mass spectrometry has been used for the analysis of strobilurin residues in wheat. The use of this novel, challenging technique, employing a direct analysis in a real time (DART) ion-source coupled with a time-of-flight mass spectrometer (TOF MS) and a desorption electrospray ionization

Characterisation of Stevia Rebaudiana by comprehensive two-dimensional liquid chromatography time-of-flight mass spectrometry

Czech Academy of Sciences Publication Activity Database

Pól, Jaroslav; Hohnová, B.; Hyötyläinen, T.

2007-01-01

Roč. 1150, 1-2 (2007), s. 85-92 ISSN 0021-9673 R&D Projects: GA AV ČR KJB4031405 Institutional research plan: CEZ:AV0Z40310501 Keywords : comprehensive two-dimensional liquid chromatography * time-of-flight mass spectrometry * Stevia rebaudiana Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.641, year: 2007

Heavy-ion accelerator mass spectrometry with a 'small' accelerator

International Nuclear Information System (INIS)

Steier, P.; Golser, R.; Priller, A.; Vockenhuber, C.; Irlweck, K.; Kutschera, W.; Lichtenstein, V.

2001-01-01

Full text: VERA, the Vienna environmental research accelerator, is based on a 3-MV pelletron tandem accelerator and is designed to allow the transport of ions of all elements, from the lightest to the heaviest. The VERA heavy ion program tries to establish measurement methods which work for the long-lived radionuclides where suppression of isobars is not required. Among these are 129 I, 210 Pb, 236 U and all heavier ions where no stable isobars exist. To suppress neighboring masses, the resolution of VERA was increased, both by improving the ion optics of existing elements and by installing a new electrostatic separator after the analyzing magnet. Interfering ions which pass all beam filters are identified with a high-resolution time-of-flight system, using a 0.5 μg/cm 2 DLC (diamond-like carbon) foil in the start detector, which substantially reduces beam straggling. Compared to heavy ion AMS at large tandem accelerators (TV ≥ 8 MV) and for cases where stable isobar interference is absent, it is possible to offset the disadvantage of lower ion energy. Moreover, the more compact facilities like VERA achieve higher stability and reliability and provide advanced computer control. This promises even higher precision and sensitivity for a larger number of samples, which is a prerequisite for research on natural-occurring heavy radioisotopes at environmental levels. First results on the measurement of 210 Pb (half-life 22 a) and 236 U (23 Ma) encourages us to push towards even heavier radionuclides (e.g. 224 Pu, 81 Ma). (author)

High precision mass measurements of thermalized relativistic uranium projectile and fission fragments with a multiple-reflection time-of-flight mass spectrometer

Energy Technology Data Exchange (ETDEWEB)

Ayet San Andres, Samuel [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany); Justus Liebig Universitaet, Giessen (Germany); Collaboration: FRS Ion Catcher-Collaboration

2016-07-01

At the FRS Ion Catcher at GSI, a relativistic beam of {sup 238}U at 1GeV/u was used to produce fission and projectile fragments on a beryllium target. The ions were separated in-flight at the FRS, thermalized in a cryogenic stopping cell and transferred to a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) where high precision mass measurements were performed. The masses of several fission and projectile fragments were measured (including short-lived nuclei with half-lives down to 18 ms) and the possibility of tailoring an isomerically clean beam for other experiments was demonstrated. With the demonstrated performance of the MR-TOF-MS and the expected production rates of exotic nuclei far from stability at the next-generation facilities such as FAIR, novel mass measurements of nuclei close to the neutron drip line will be possible and key information for understanding the r-process will be available. The results from the last experiment and an outlook of possible future mass measurements close to the neutron drip line at FAIR with the MR-TOF-MS are presented.

Time-of-flight spectrometers

International Nuclear Information System (INIS)

Carrico, J.P.

1976-01-01

The flight time of an ion in an inhomogeneous, oscillatory electric field (IOFE) is an m/e-dependent property of this field and is independent of the initial position and velocity. The d.c. component of the equation of motion for an ion in the IOFE describes a harmonic oscillation of constant period. When ions oscillate for many periods with one species overtaking another the motion may no longer be truly periodic although the resulting period or 'quasi-period' still remains independent of the initial conditions. This period or 'quasi-period' is used in the time-of-flight mass spectrometer described. The principle of operation is also described and both analytical and experimental results are reported. (B.D.)

A new Time-of-Flight mass measurement project for exotic nuclei and ultra-high precision detector development

Directory of Open Access Journals (Sweden)

Sun Bao-Hua

2016-01-01

Full Text Available The time-of-flight (TOF mass spectrometry (MS, a high-resolution magnetic spectrometer equipped with a fast particle tracking system, is well recognized by its ability in weighing the most exotic nuclei. Currently such TOF-MS can achieve a mass resolution power of about 2×10−4. We show that the mass resolution can be further improved by one order of magnitude with augmented timing and position detectors. We report the progress in developing ultra-fast detectors to be used in TOF-MS.

Picosecond resolution on relativistic heavy ions' time-of-flight measurement

International Nuclear Information System (INIS)

Ebran, A.; Taieb, J.; Belier, G.; Chatillon, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.

2013-01-01

We developed a time-of-flight measurement system for relativistic heavy ions with a requested resolution of 40 ps Full Width Half Maximum. Such a resolution is mandatory to assign the correct mass number to every fission fragment, identified using the Bρ-ToF-ΔE method with the recoil spectrometer designed for the SOFIA experiment—which hold very recently at GSI. To achieve such a performance, fast plastic scintillators read-out by dedicated photomultiplier tubes were chosen among other possible options. We have led several test-measurements from 2009 to 2011, in order to investigate: the effect of the addition of a quenching molecule in the scintillator's matrix, the influence of the detector's size and the impact of the photomultiplier tube. The contribution of the dedicated electronics is also characterized. Time-of-flight measurements were performed realized with electron pulses and relativistic heavy ions, respectively provided by the LASER driven electron–accelerator (ELSA) at CEA–DAM Ile-de-France and by the SIS18/FRS facility at GSI. The reported results exhibit a time resolution better than 20 ps Full Width Half Maximum reached with the last prototype at GSI with an Uranium beam. These results confirm that the SOFIA experiment should enable the measurement of the relativistic fission fragments' time-of-flight with the requested resolution

Phenotypic identification of Porphyromonas gingivalis validated with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

NARCIS (Netherlands)

Rams, Thomas E; Sautter, Jacqueline D; Getreu, Adam; van Winkelhoff, Arie J

OBJECTIVE: Porphyromonas gingivalis is a major bacterial pathogen in human periodontitis. This study used matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry to assess the accuracy of a rapid phenotypic identification scheme for detection of cultivable P.

Short communication: Identification of subclinical cow mastitis pathogens in milk by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Science.gov (United States)

Barreiro, J R; Ferreira, C R; Sanvido, G B; Kostrzewa, M; Maier, T; Wegemann, B; Böttcher, V; Eberlin, M N; dos Santos, M V

2010-12-01

Subclinical mastitis is a common and easily disseminated disease in dairy herds. Its routine diagnosis via bacterial culture and biochemical identification is a difficult and time-consuming process. In this work, we show that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows bacterial identification with high confidence and speed (1 d for bacterial growth and analysis). With the use of MALDI-TOF MS, 33 bacterial culture isolates from milk of different dairy cows from several farms were analyzed, and the results were compared with those obtained by classical biochemical methods. This proof-of-concept case demonstrates the reliability of MALDI-TOF MS bacterial identification, and its increased selectivity as illustrated by the additional identification of coagulase-negative Staphylococcus species and mixed bacterial cultures. Matrix-assisted laser desorption-ionization mass spectrometry considerably accelerates the diagnosis of mastitis pathogens, especially in cases of subclinical mastitis. More immediate and efficient animal management strategies for mastitis and milk quality control in the dairy industry can therefore be applied. Copyright © 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

First on-line applications of multi-reflection time-of-flight mass separator at ISOLTRAP and the mass measurement of $^{82}$Zn

CERN Document Server

Wolf, Robert

This thesis describes the implementation and first on-line application of a multi-reflection time-of-flight (MR-ToF) mass analyzer for high-resolution mass separation at the ISOLTRAP mass spectrometer at ISOLDE/CERN. On the one hand, the major objective was to improve ISOLTRAPs mass-measurement capabilities with respect to the ratio of delivered contaminating ions to ions of interest. On the other hand, the time necessary to purify wanted from unwanted species should be reduced as much as possible to enable access to even more exotic nuclei. The device has been set up, optimized and tested at the University of Greifswald before its move to ISOLTRAP. The achieved performance comprises mass resolving powers of up to 200000 reached at observation times of 30ms and a contamination suppression of about four orders of magnitude by use of a Bradbury-Nielsen gate. With the characteristics, it outperforms clearly the so far state-of-the-art purification method of a gas-filled Penning trap. To improve the utilization o...

Accelerator-based ultrasensitive mass spectrometry

International Nuclear Information System (INIS)

Gove, H.E.

1985-01-01

This chapter describes a new mass spectrometry technique involving charged particle accelerators normally used for basic research in nuclear science. Topics considered include the limitations of conventional mass spectrometry, the limitations of the direct measurement of radioactive decay, mass spectrometry using a tandem electrostatic accelerator, mass spectrometry using a cyclotron, how accelerator mass spectrometry circumvents the limitations of conventional mass spectrometry, measurements of stable isotopes, nuclear physics and astrophysics applications, modifications to existing accelerators, descriptions of dedicated systems, and future applications

[Special application of matrix-assisted laser desorption ionization time-of-flight mass spectrometry in clinical microbiological diagnostics].

Science.gov (United States)

Nagy, Erzsébet; Abrók, Marianna; Bartha, Noémi; Bereczki, László; Juhász, Emese; Kardos, Gábor; Kristóf, Katalin; Miszti, Cecilia; Urbán, Edit

2014-09-21

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry as a new possibility for rapid identification of bacteria and fungi revolutionized the clinical microbiological diagnostics. It has an extreme importance in the routine microbiological laboratories, as identification of the pathogenic species rapidly will influence antibiotic selection before the final determination of antibiotic resistance of the isolate. The classical methods for identification of bacteria or fungi, based on biochemical tests, are influenced by many environmental factors. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry is a rapid method which is able to identify a great variety of the isolated bacteria and fungi based on the composition of conserved ribosomal proteins. Recently several other applications of the method have also been investigated such as direct identification of pathogens from the positive blood cultures. There are possibilities to identify bacteria from the urine samples in urinary tract infection or from other sterile body fluids. Using selective enrichment broth Salmonella sp from the stool samples can be identified more rapidly, too. The extended spectrum beta-lactamase or carbapenemase production of the isolated bacteria can be also detected by this method helping the antibiotic selection in some cases. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry based methods are suitable to investigate changes in deoxyribonucleic acid or ribonucleic acid, to carry out rapid antibiotic resistance determination or other proteomic analysis. The aim of this paper is to give an overview about present possibilities of using this technique in the clinical microbiological routine procedures.

Detection of Bacteriocins by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

OpenAIRE

Rose, Natisha L.; Sporns, Peter; McMullen, Lynn M.

1999-01-01

The use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the detection of bacteriocins was investigated. A 30-s water wash of the sample on the MALDI-TOF MS probe was effective in removing contaminants of the analyte. This method was used for rapid detection of nisin, pediocin, brochocin A and B, and enterocin A and B from culture supernatants and for detection of enterocin B throughout its purification.

Derivatization of Dextran for Multiply Charged Ion Formation and Electrospray Ionization Time-of-Flight Mass Spectrometric Analysis

Science.gov (United States)

Tapia, Jesus B.; Hibbard, Hailey A. J.; Reynolds, Melissa M.

2017-10-01

We present the use of a simple, one-pot derivatization to allow the polysaccharide dextran to carry multiple positive charges, shifting its molecular weight distribution to a lower m/ z range. We performed this derivatization because molecular weight measurements of polysaccharides by mass spectrometry are challenging because of their lack of readily ionizable groups. The absence of ionizable groups limits proton abstraction and suppresses proton adduction during the ionization process, producing mass spectra with predominantly singly charged metal adduct ions, thereby limiting the detection of large polysaccharides. To address this challenge, we derivatized dextran T1 (approximately 1 kDa) by attaching ethylenediamine, giving dextran readily ionizable, terminal amine functional groups. The attached ethylenediamine groups facilitated proton adduction during the ionization process in positive ion mode. Using the low molecular weight dextran T1, we tracked the number of ethylenediamine attachments by measuring the mass shift from underivatized to derivatized dextran T1. Using electrospray ionization time-of-flight mass spectrometry, we observed derivatized dextran chains ranging from two to nine glucose residues with between one and four attachments/charges. Our success in shifting derivatized dextran T1 toward the low m/ z range suggests potential for this derivatization as a viable route for analysis of high molecular weight polysaccharides using electrospray ionization time-of-flight mass spectrometry. [Figure not available: see fulltext.

Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions

Science.gov (United States)

Getty, S. A.; Brinckerhoff, W. B.; Cornish, T.; Ecelberger, S. A.; Li, X.; Floyd, M. A. Merrill; Chanover, N.; Uckert, K.; Voelz, D.; Xiao, X.;

Picosecond resolution on relativistic heavy ions' time-of-flight measurement

Energy Technology Data Exchange (ETDEWEB)

Ebran, A., E-mail: adeline.ebran@cea.fr; Taieb, J., E-mail: julien.taieb@cea.fr; Belier, G.; Chatillon, A.; Laurent, B.; Martin, J.-F.; Pellereau, E.

2013-11-11

We developed a time-of-flight measurement system for relativistic heavy ions with a requested resolution of 40 ps Full Width Half Maximum. Such a resolution is mandatory to assign the correct mass number to every fission fragment, identified using the Bρ-ToF-ΔE method with the recoil spectrometer designed for the SOFIA experiment—which hold very recently at GSI. To achieve such a performance, fast plastic scintillators read-out by dedicated photomultiplier tubes were chosen among other possible options. We have led several test-measurements from 2009 to 2011, in order to investigate: the effect of the addition of a quenching molecule in the scintillator's matrix, the influence of the detector's size and the impact of the photomultiplier tube. The contribution of the dedicated electronics is also characterized. Time-of-flight measurements were performed realized with electron pulses and relativistic heavy ions, respectively provided by the LASER driven electron–accelerator (ELSA) at CEA–DAM Ile-de-France and by the SIS18/FRS facility at GSI. The reported results exhibit a time resolution better than 20 ps Full Width Half Maximum reached with the last prototype at GSI with an Uranium beam. These results confirm that the SOFIA experiment should enable the measurement of the relativistic fission fragments' time-of-flight with the requested resolution.

Design and utilization of a Flight Test Engineering Database Management System at the NASA Dryden Flight Research Facility

Science.gov (United States)

Knighton, Donna L.

1992-01-01

A Flight Test Engineering Database Management System (FTE DBMS) was designed and implemented at the NASA Dryden Flight Research Facility. The X-29 Forward Swept Wing Advanced Technology Demonstrator flight research program was chosen for the initial system development and implementation. The FTE DBMS greatly assisted in planning and 'mass production' card preparation for an accelerated X-29 research program. Improved Test Plan tracking and maneuver management for a high flight-rate program were proven, and flight rates of up to three flights per day, two times per week were maintained.

Screening and confirmation criteria for hormone residue analysis using liquid chromatography accurate mass time-of-flight, Fourier transform ion cyclotron resonance and orbitrap mass spectrometry techniques

NARCIS (Netherlands)

Nielen, M.W.F.; Engelen, M.C. van; Zuiderent, R.; Ramaker, R.

2007-01-01

An emerging trend is recognised in hormone and veterinary drug residue analysis from liquid chromatography tandem mass spectrometry (LC/MS/MS) based screening and confirmation towards accurate mass alternatives such as LC coupled with time-of-flight (TOF), Fourier transform ion cyclotron resonance

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.

Analysis of phosphatidylcholine oxidation products in human plasma using quadrupole time-of flight mass spectrometry

OpenAIRE

Adachi, Junko; Asano, Migiwa; Yoshioka, Naoki; Nushida, Hideyuki; Ueno, Yasuhiro

2006-01-01

We report here an application of the previous method for the analysis ofphosphatidylcholine (PC) and lysophosphatidylcholine (lysoPC) oxidation products inhuman plasma using quadrupole time of flight (Q-TOF) mass spectrometry withelectrospray ionization. We separated these products using an HPLC C8 column witha gradient of methanol and 10 mM aqueous ammonium acetate. Monohydroperoxides,epoxyhydroxy derivatives, oxo derivatives, and trihydroxides of palmitoyl-linoleoyl(C16:0/C18:2) PC and stea...

Ion optics of a new time-of-flight mass spectrometer for quantitative surface analysis

International Nuclear Information System (INIS)

Veryovkin, Igor V.; Calaway, Wallis F.; Pellin, Michael J.

2004-01-01

A new time-of-flight instrument for quantitative surface analysis was developed and constructed at Argonne National Laboratory. It implements ion sputtering and laser desorption for probing analyzed samples and can operate in regimes of secondary neutral mass spectrometry with laser post-ionization and secondary ion mass spectrometry. The instrument incorporates two new ion optics developments: (1) 'push-pull' front end ion optics and (2) focusing and deflecting lens. Implementing these novel elements significantly enhance analytical capabilities of the instrument. Extensive three-dimensional computer simulations of the instrument were conducted in SIMION 3D (c) to perfect its ion optics. The operating principles of the new ion optical systems are described, and a scheme of the new instrument is outlined together with its operating modes

A homemade high-resolution orthogonal-injection time-of-flight mass spectrometer with a heated capillary inlet

International Nuclear Information System (INIS)

Guo Changjuan; Huang Zhengxu; Gao Wei; Nian Huiqing; Chen Huayong; Dong Junguo; Shen Guoying; Fu Jiamo; Zhou Zhen

2008-01-01

We describe a homemade high-resolution orthogonal-injection time-of-flight (O-TOF) mass spectrometer combing a heated capillary inlet. The O-TOF uses a heated capillary tube combined with a radio-frequency only quadrupole (rf-only quadrupole) as an interface to help the ion transmission from the atmospheric pressure to the low-pressure regions. The principle, configuration of the O-TOF, and the performance of the instrument are introduced in this paper. With electrospray ion source, the performances of the mass resolution, the sensitivity, the mass range, and the mass accuracy are described. We also include our results obtained by coupling atmospheric pressure matrix-assisted laser deporption ionization with this instrument

Two-step Laser Time-of-Flight Mass Spectrometry to Elucidate Organic Diversity in Planetary Surface Materials.

Science.gov (United States)

Getty, Stephanie A.; Brinckerhoff, William B.; Cornish, Timothy; Li, Xiang; Floyd, Melissa; Arevalo, Ricardo Jr.; Cook, Jamie Elsila; Callahan, Michael P.

2013-01-01

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) holds promise to be a low-mass, compact in situ analytical capability for future landed missions to planetary surfaces. The ability to analyze a solid sample for both mineralogical and preserved organic content with laser ionization could be compelling as part of a scientific mission pay-load that must be prepared for unanticipated discoveries. Targeted missions for this instrument capability include Mars, Europa, Enceladus, and small icy bodies, such as asteroids and comets.

First on-line applications of a multi-reflection time-of-flight mass separator at ISOLTRAP and the mass measurement of 82Zn

International Nuclear Information System (INIS)

Wolf, Robert

2013-01-01

This thesis describes the implementation and first on-line application of a multi-reflection time-of-flight (MR-ToF) mass analyzer for high-resolution mass separation at the ISOLTRAP mass spectrometer at ISOLDE/CERN. On the one hand, the major objective was to improve ISOLTRAPs mass-measurement capabilities with respect to the ratio of delivered contaminating ions to ions of interest. On the other hand, the time necessary to purify wanted from unwanted species should be reduced as much as possible to enable access to even more exotic nuclei. The device has been set up, optimized and tested at the University of Greifswald before its move to ISOLTRAP. The achieved performance comprises mass resolving powers of up to 2 x 10 5 reached at observation times of 30 ms and a contamination suppression of about four orders of magnitude by use of a Bradbury-Nielsen gate. With the characteristics, it outperforms clearly the so far state-of-the-art purification method of a gas-filled Penning trap. To improve the utilization of the MR-ToF mass analyzer, the in-trap lift method has been developed. It simplifies the application and optimization of the device, which is a crucial time factor in an on-line experiment. The device was the first of its kind successfully applied to radioactive ion beams for a mass analysis, for a mass separation (in combination with the Bradbury-Nielsen gate) as a preparatory step for a subsequent Penning-trap mass measurement and as a high-precision mass spectrometer of its own. The later was recently used for the first mass measurement of the neutron-rich calcium isotopes 53 Ca and 54 Ca. The so-far achieved mass-resolving power of 2 x 10 5 belongs to the highest reported for time-of-flight mass analyzers at all. The first successful application of the MR-ToF system as the only mass separator at ISOLTRAP resulted in the mass measurement of 82 Zn. The new mass value has been compared to mass extrapolations of the most recent Hartree-Fock-Bogolyubov (HFB

Radiofrequency glow discharge time of flight mass spectrometry: pulsed vs. continuous mode

International Nuclear Information System (INIS)

Lobo, L.; Pereiro, R.; Sanz-Medel, A.; Bordel, N.; Tempez, A.; Chapon, P.; Hohl, M.; Michler, J.

2009-01-01

Full text: Glow discharge (GD) is a well established tool for the direct analysis of solids. The application field of the original direct current GD, restricted to conductive samples, has been extended by radiofrequency powered GDs that can be applied for conductive and non-conductive samples. Moreover, the introduction of pulsed GD has opened the possibility of applying higher instantaneous powers that can improve the atomization-ionization processes and therefore the sensitivity. Furthermore, pulsed-GD may enable temporal separation of discharge gas species from the sample ions. In this work the analytical performances of radiofrequency and pulsed radiofrequency glow discharges are evaluated by using a time of flight mass analyzer (TOFMS). (author)

Accurate mass analysis of ethanesulfonic acid degradates of acetochlor and alachlor using high-performance liquid chromatography and time-of-flight mass spectrometry

Science.gov (United States)

Thurman, E.M.; Ferrer, I.; Parry, R.

2002-01-01

Degradates of acetochlor and alachlor (ethanesulfonic acids, ESAs) were analyzed in both standards and in a groundwater sample using high-performance liquid chromatography-time-of-flight mass spectrometry with electrospray ionization. The negative pseudomolecular ion of the secondary amide of acetochlor ESA and alachlor ESA gave average masses of 256.0750??0.0049 amu and 270.0786??0.0064 amu respectively. Acetochlor and alachlor ESA gave similar masses of 314.1098??0.0061 amu and 314.1153??0.0048 amu; however, they could not be distinguished by accurate mass because they have the same empirical formula. On the other hand, they may be distinguished using positive-ion electrospray because of different fragmentation spectra, which did not occur using negative-ion electrospray.

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

Phonon-assisted field emission in silicon nanomembranes for time-of-flight mass spectrometry of proteins.

Science.gov (United States)

Park, Jonghoo; Aksamija, Zlatan; Shin, Hyun-Cheol; Kim, Hyunseok; Blick, Robert H

2013-06-12

Time-of-flight (TOF) mass spectrometry has been considered as the method of choice for mass analysis of large intact biomolecules, which are ionized in low charge states by matrix-assisted-laser-desorption/ionization (MALDI). However, it remains predominantly restricted to the mass analysis of biomolecules with a mass below about 50,000 Da. This limitation mainly stems from the fact that the sensitivity of the standard detectors decreases with increasing ion mass. We describe here a new principle for ion detection in TOF mass spectrometry, which is based upon suspended silicon nanomembranes. Impinging ion packets on one side of the suspended silicon nanomembrane generate nonequilibrium phonons, which propagate quasi-diffusively and deliver thermal energy to electrons within the silicon nanomembrane. This enhances electron emission from the nanomembrane surface with an electric field applied to it. The nonequilibrium phonon-assisted field emission in the suspended nanomembrane connected to an effective cooling of the nanomembrane via field emission allows mass analysis of megadalton ions with high mass resolution at room temperature. The high resolution of the detector will give better insight into high mass proteins and their functions.

Research on the Frequency Aliasing of Resistance Acceleration Guidance for Reentry Flight

Directory of Open Access Journals (Sweden)

Han Pengxin

2017-01-01

Full Text Available According to the special response of resistance acceleration during hypersonic reentry flight, different guidance frequency will result to very different flight and control response. The analysis model for the response of resistance acceleration to the attack angle and dynamic press is put forward respectively in this paper. And the frequency aliasing phenomenon of guidance is revealed. The simulation results to the same vehicle sufficiently substantiate the frequency aliasing of resistance acceleration during reentry guidance.

Comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry peak sorting algorithm.

Science.gov (United States)

Oh, Cheolhwan; Huang, Xiaodong; Regnier, Fred E; Buck, Charles; Zhang, Xiang

2008-02-01

We report a novel peak sorting method for the two-dimensional gas chromatography/time-of-flight mass spectrometry (GC x GC/TOF-MS) system. The objective of peak sorting is to recognize peaks from the same metabolite occurring in different samples from thousands of peaks detected in the analytical procedure. The developed algorithm is based on the fact that the chromatographic peaks for a given analyte have similar retention times in all of the chromatograms. Raw instrument data are first processed by ChromaTOF (Leco) software to provide the peak tables. Our algorithm achieves peak sorting by utilizing the first- and second-dimension retention times in the peak tables and the mass spectra generated during the process of electron impact ionization. The algorithm searches the peak tables for the peaks generated by the same type of metabolite using several search criteria. Our software also includes options to eliminate non-target peaks from the sorting results, e.g., peaks of contaminants. The developed software package has been tested using a mixture of standard metabolites and another mixture of standard metabolites spiked into human serum. Manual validation demonstrates high accuracy of peak sorting with this algorithm.

Characterization of a time-of-flight mass spectrometer and its applications in the study of solid surfaces; Charakterisierung eines Flugzeitmassenspektrometers und seine Anwendungen in der Festkoerperoberflaechenuntersuchung

Energy Technology Data Exchange (ETDEWEB)

Mazarov, P.

2006-12-21

The object and the purpose of the present work was to develop, to assemble and to start running a new TOF (time of flight) mass spectrometer for imaging SNMS analytic which is optimized for the analysis of highly molecular secondary ions. The most important purpose was the characterization of the TOF mass spectrometer. The obtained mass spectra of indium, tantalum and silver clusters reflect the excellent properties of the TOF mass spectrometer for the detection of large clusters with good detection efficiency up to masses of 16000 amu. The possibility of the deflection of selected saturated atom and cluster peaks serves for further improvement of the detection efficiency for large molecules. The accessible mass resolution was determined to be of the order of m/{delta}m=1000 in the high mass region. Numerous measurements were carried out to characterize the useful yield of this spectrometer. For a best possible adaptation of the TOF mass spectrometer for the detection of highly molecular particles, a device for post-acceleration of the detected particles by up to 10 keV were inserted directly before the MCP detector. The detection efficiency of positive secondary ions was determined for different post-acceleration voltages for the example of sputtered indium cluster ions. In addition, a new method was developed for the quantitative determination of the spectral ionization probability {alpha}{sup +}({nu}) of sputtered particles as a function of the emission velocity. The next application of the TOF mass spectrometer is the analysis of complicated organic molecules in solid state surfaces. During measurements of the photo-ionization behaviour of neutral tryptophan molecules, it was found out that a stable molecular ion signal is generated in the SNMS spectrum with h{nu}=7.9 eV can only be observed by the use of a continuous ion beam or very long (ms range) ion pulses. (orig.)

Identification of molecules in graphite furnace by laser ionization time-of-flight mass spectrometry: sulfur and chlorine containing compounds

CSIR Research Space (South Africa)

Raseleka, RM

2004-01-01

Full Text Available An electro thermal vaporizer (ETV) coupled to a time-of-flight mass spectrometer (TOF-MS) with laser ionization (LI) was applied to the identification of molecules from sulphur and chlorine matrices in the furnace. An interface was developed...

Peroxy Radicals Observed in a Forested Environment with Time of Flight Mass Spectrometry

Science.gov (United States)

Cantrell, C. A.; Mauldin, L.; Nowak, J. B.

2017-12-01

Observations of peroxy radicals were made using time-of-flight chemical ionization mass spectrometry (ToF-CIMS) during the PROPHET-AMOS (Program for Research on Oxidants, Photochemistry, Emissions and Transport - Atmospheric Measurements of Oxidants in Summer) campaign in summer 2016 at the University of Michigan Biological Station (UMBS) in the northern lower peninsula of Michigan. The environment is one of high isoprene productivity and generally low NOx, depending on the origin of air masses that are sampled, and has been the subject of several comprehensive atmospheric observational studies. The ToF-CIMS was configured to measure OH, HO2+RO2, and extremely oxygenated volatile organic compounds (ELVOCs) in a cycle of about 5 minutes for each. This presentation examines the time- and chemical coordinate-dependent behavior of the peroxy radicals, and compares the observations with models that are constrained by observations of the controlling variables. The results are used to estimate factors such as the photochemical production rate of ozone and other atmospheric oxidation parameters for this remote forest site.

Time-of-flight secondary ion mass spectrometry with energetic cluster ion impact ionization for highly sensitive chemical structure characterization

Energy Technology Data Exchange (ETDEWEB)

Hirata, K., E-mail: k.hirata@aist.go.jp [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Saitoh, Y.; Chiba, A.; Yamada, K.; Narumi, K. [Takasaki Advanced Radiation Research Institute (TARRI), Japan Atomic Energy Agency (JAEA), Takasaki, Gumma 370-1292 (Japan)

2013-11-01

Energetic cluster ions with energies of the order of sub MeV or greater were applied to time-of-flight (TOF) secondary ion (SI) mass spectrometry. This gave various advantages including enhancement of SIs required for chemical structure characterization and prevention of charging effects in SI mass spectra for organic targets. We report some characteristic features of TOF SI mass spectrometry using energetic cluster ion impact ionization and discuss two future applications of it.

Preanalytical and analytical variation of surface-enhanced laser desorption-ionization time-of-flight mass spectrometry of human serum

DEFF Research Database (Denmark)

Albrethsen, Jakob; Bøgebo, Rikke; Olsen, Jesper

2006-01-01

BACKGROUND: Surface-enhanced laser desorption-ionization time-of-flight (SELDI-TOF) mass spectrometry of human serum is a potential diagnostic tool in human diseases. In the present study, the preanalytical and analytical variation of SELDI-TOF mass spectrometry of serum was assessed in healthy...... was 18% (6%-34%, n=4) for 16 peaks, and inter-individual CV was 38% (16%-56%, n=16) for 20 peaks. CONCLUSIONS: The pre-analytical and analytical conditions of SELDI-TOF mass spectrometry of serum have a significant impact on the protein peaks, with the number of peaks low and the assay variation high...

A multiple-orbit time-of-flight mass spectrometer based on a low energy electrostatic storage ring

Science.gov (United States)

Sullivan, M. R.; Spanjers, T. L.; Thorn, P. A.; Reddish, T. J.; Hammond, P.

2012-11-01

The results are presented for an electrostatic storage ring, consisting of two hemispherical deflector analyzers (HDA) connected by two separate sets of cylindrical lenses, used as a time-of-flight mass spectrometer. Based on the results of charged particle simulations and formal matrix model, the Ion Storage Ring is capable of operating with multiple stable orbits, for both single and multiply charged ions simultaneously.

Gas chromatographic quadrupole time-of-flight full scan high resolution mass spectrometric screening of human urine in antidoping analysis

NARCIS (Netherlands)

Abushareeda, Wadha; Lyris, Emmanouil; Kraiem, Suhail; Wahaibi, Aisha Al; Alyazidi, Sameera; Dbes, Najib; Lommen, Arjen; Nielen, Michel; Horvatovich, Peter L.; Alsayrafi, Mohammed; Georgakopoulos, Costas

2017-01-01

This paper presents the development and validation of a high-resolution full scan (FS) electron impact ionization (EI) gas chromatography coupled to quadrupole Time-of-Flight mass spectrometry (GC/QTOF) platform for screening anabolic androgenic steroids (AAS) in human urine samples. The World

Design of a reflex time-of-flight mass spectrometer for the study of the desorption of molecular ions

International Nuclear Information System (INIS)

Riggi, F.

1991-01-01

A reflex time-of-flight mass spectrometer for the study of the desorption and dissociation of molecular ions has been designed. A general overview of the instrument is reported, together with the different experimental aspects of the technique. These include mechanical and vacuum solutions, secondary ion optics in the electrostatic mirror, electronics, data acquisition and analysis

Matrix effect in analysis of pesticide residues in fruits and vegetables by high performance liquid chromatography with quadrupole-time of flight mass spectrometry

Directory of Open Access Journals (Sweden)

Andoralov A.M.

2017-03-01

Full Text Available For modern food safety control are using techniques that allow to determinate a large number of components. So for determination of pesticide residues in fruits and vegetables commonly used methods of gas and liquid chromatography with time-of-flight mass-spectrometric detection. This system allows to carry out quantitative determination several hundreds of pesticides and their identification by the characteristic fragments of the mass spectrum. The main problem when using mass spectrometric detection is a matrix effect, which is caused by the influence of matrix components extracted with pesticides from the sample. In this work, attempts have been made to reduce the influence of the matrix in the analysis of pesticide residues by high performance liquid chromatography with time of flight mass spectrometry (HPLC / TOFMS.

SHMS Hodoscopes and Time of Flight System

Science.gov (United States)

Craycraft, Kayla; Malace, Simona

2017-09-01

As part of the Thomas Jefferson National Accelerator Facility's (Jefferson Lab) upgrade from 6 GeV to 12 GeV, a new magnetic focusing spectrometer, the Super High Momentum Spectrometer (SHMS), was installed in experimental Hall C. The detector stack consists of horizontal drift chambers for tracking, gas Cerenkov and Aerogel detectors and a lead glass calorimeter for particle identification. A hodoscope system consisting of three planes of scintillator detectors (constructed by James Madison University) and one plane of quartz bars (built by North Carolina A&T State University) is used for triggering and time of flight measurements. This presentation consists of discussion of the installation, calibration, and characterization of the detectors used in this Time of Flight system. James Madison University, North Carolina A&T State University.

Gas chromatographic quadrupole time-of-flight full scan high resolution mass spectrometric screening of human urine in antidoping analysis

NARCIS (Netherlands)

Abushareeda, Wadha; Lyris, Emmanouil; Kraiem, Suhail; Wahaibi, Aisha Al; Alyazidi, Sameera; Dbes, Najib; Lommen, Arjen; Nielen, Michel; Horvatovich, Peter L.; Alsayrafi, Mohammed; Georgakopoulos, Costas

2017-01-01

This paper presents the development and validation of a high-resolution full scan (FS) electron impact ionization (EI) gas chromatography coupled to quadrupole Time-of-Flight mass spectrometry (GC/QTOF) platform for screening anabolic androgenic steroids (AAS) in human urine samples. The World

First Isochronous Time-of-Flight Mass Measurements of Short-Lived Projectile Fragments in the ESR

International Nuclear Information System (INIS)

Stadlmann, J.; Geissel, H.; Hausmann, M.; Nolden, F.; Radon, T.; Schatz, H.; Scheidenberger, C.; Attallah, F.; Beckert, K.; Bosch, F.; Falch, M.; Franczak, B.; Franzke, B.; Kerscher, Th.; Klepper, O.; Kluge, H.J.; Kozhuharov, C.; Loebner, K.E.G.; Muenzenberg, G.; Novikov, Yu.N.; Steck, M.; Sun, Z.; Suemmerer, K.; Weick, H.; Wollnik, H.

2000-01-01

A new method for precise mass measurements of short-lived hot nuclei is presented. These nuclei were produced via projectile fragmentation, separated with the FRS and injected into the storage ring ESR being operated in the isochronous mode. The revolution time of the ions is measured with a time-of-flight detector sensitive to single particles. This new method allows access to exotic nuclei with half-lives in the microsecond region. First results from this novel method obtained with measurements on neutron-deficient fragments of a chromium primary beam with half-lives down to 50 ms are reported. A precision of deltam/m ≤ 5 · 10 -6 has been achieved

Accelerations in Flight

Science.gov (United States)

Doolittle, J H

1925-01-01

This work on accelerometry was done at McCook Field for the purpose of continuing the work done by other investigators and obtaining the accelerations which occur when a high-speed pursuit airplane is subjected to the more common maneuvers. The accelerations obtained in suddenly pulling out of a dive with well-balanced elevators are shown to be within 3 or 4 per cent of the theoretically possible accelerations. The maximum acceleration which a pilot can withstand depends upon the length of time the acceleration is continued. It is shown that he experiences no difficulty under the instantaneous accelerations as high as 7.8 G., but when under accelerations in excess of 4.5 G., continued for several seconds, he quickly loses his faculties.

Determination of four major saponins in the seeds of Aesculus chinensis Bunge using accelerated solvent extraction followed by high-performance liquid chromatography and electrospray-time of flight mass spectrometry.

Science.gov (United States)

Chen, Junhui; Li, Wenlong; Yang, Baijuan; Guo, Xiuchun; Lee, Frank Sen-Chun; Wang, Xiaoru

2007-07-23

A new method based on accelerated solvent extraction (ASE) followed by a reliable high-performance liquid chromatography-diode array detector (HPLC-DAD) and positive ion electrospray-time of flight mass spectrometry (ESI-TOF/MS) analysis has been developed for the characterization and quantification of four major saponins in extracts of the seeds of Aesculus chinensis Bunge (semen aesculi). The saponins escin Ia, escin Ib, isoescin Ia and isoescin Ib were extracted from seeds of A. chinesis Bunge via ASE, and the operational parameters of ASE were optimized, such as extraction solvent, extraction temperature, static extraction time and extraction cycles. The optimized procedure employed 70% MeOH as extraction solvent, 120 degrees C of extraction temperature, 7 min of static extraction time, 60% flush volume and the extraction recoveries of the four compounds were nearly to 100% for two cycles. The HPLC conditions are as follows: SinoChrom ODS BP C18 (4.6 mm x 200 mm, 5 microm) column, acetonitrile and 0.10% phosphoric acid solution as mobile phase, flow rate is 1.0 mL min(-1), detection length of UV is 203 nm, injection volume is 10 microL. The results indicated that the developed HPLC method is simple, sensitive and reliable for the determination of four major saponins in seeds of A. chinesis Bunge with a good linearity (r2 > 0.9994), precision (relative standard deviation (R.S.D.) < 1.5%) and the recovery ranges of 95.2-97.3%. The limits of detection (LOD) of the four compounds were in the range of 0.40-0.75 microg mL(-1). This assay can be readily utilized as a quality control method for semen aesculi and other related medicinal plants.

Time of flight secondary ion mass spectrometry: A powerful high throughput screening tool

International Nuclear Information System (INIS)

Smentkowski, Vincent S.; Ostrowski, Sara G.

2007-01-01

Combinatorial materials libraries are becoming more complicated; successful screening of these libraries requires the development of new high throughput screening methodologies. Time of flight secondary ion mass spectrometry (ToF-SIMS) is a surface analytical technique that is able to detect and image all elements (including hydrogen which is problematic for many other analysis instruments) and molecular fragments, with high mass resolution, during a single measurement. Commercial ToF-SIMS instruments can image 500 μm areas by rastering the primary ion beam over the region of interest. In this work, we will show that large area analysis can be performed, in one single measurement, by rastering the sample under the ion beam. We show that an entire 70 mm diameter wafer can be imaged in less than 90 min using ToF-SIMS stage (macro)rastering techniques. ToF-SIMS data sets contain a wealth of information since an entire high mass resolution mass spectrum is saved at each pixel in an ion image. Multivariate statistical analysis (MVSA) tools are being used in the ToF-SIMS community to assist with data interpretation; we will demonstrate that MVSA tools provide details that were not obtained using manual (univariate) analysis

Multi-detection of corticosteroids in sports doping and veterinary control using high-resolution liquid chromatography/time-of-flight mass spectrometry

NARCIS (Netherlands)

Touber, M.E.; Engelen, M.C.; Georgakopoulus, C.; Rhijn, van J.A.; Nielen, M.W.F.

2007-01-01

A liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS) method was developed using the latest high-resolution LC column technology, the ultra performance liquid chromatography (UPLC (TM)), and electrospray ionization (ESI) in the positive ion mode. Gradient UPLC separation conditions

Identification of Wheat Varieties Using Matrix-assisted Laser Desorption/Ionisation Time-of-flight Mass Spectrometry and an Artificial Neural network

DEFF Research Database (Denmark)

Bloch, Helle Aagaard; Kesmir, Can; Petersen, Marianne Kjerstine

1999-01-01

A novel tool for variety identification of wheat (Triticum aestivum L,) has been developed: an artificial neural network (ANN) is used to classify the gliadin fraction analysed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS). The robustness...

Determination of organic compounds in nano-particles by laser breakdown and resonant ionization time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Deguchi, Yoshihiro; Tanaka, Nobuyuki

2005-01-01

Laser breakdown and resonance ionization time-of-flight mass spectrometry (TOFMS) with a differential mobility analyzer (DMA) was developed and applied to detect compositions and organic substances in nano-particles. The laser breakdown TOFMS method is capable of reaching pptv sensitivity, which is generally much better than the normal LIBS techniques. The system was demonstrated to successfully detect signals in the mass range of 1 to 300 amu for 60 and 140 nm particles in diesel engine exhaust. The detected signals showed that the nano-particles contained both aromatic and chain hydrocarbons

Design and realization of a space-borne reflectron time of flight mass spectrometer: electronics and measuring head

International Nuclear Information System (INIS)

Devoto, P.

2006-03-01

The purpose of this thesis is the design of the electronics of a time of flight mass spectrometer, the making and the vacuum tests of a prototype which can be put onboard a satellite. A particular effort was necessary to decrease to the maximum the mass and electric consumption of the spectrometer, which led to the development of new circuits. The work completed during this thesis initially concerns the electronics of the measuring equipment which was conceived in a concern for modularity. A complete 'reflectron' type mass spectrometer was then designed, simulated and developed. The built prototype, which uses the developed electronics, was exposed to ion flows of different masses and energies in the CESR vacuum chambers. Its measured performances validate the implemented principles and show that an identical mass spectrometer can be put onboard a satellite with profit, for planetary or solar missions. (author)

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry (MALDI-TOF MS)

Science.gov (United States)

Idelevich, Evgeny A.; Grünastel, Barbara

2016-01-01

ABSTRACT Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption–ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. PMID:27795344

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).

Science.gov (United States)

Idelevich, Evgeny A; Grünastel, Barbara; Becker, Karsten

2017-01-01

Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. Copyright © 2016 American Society for Microbiology.

Development of an ion time-of-flight spectrometer for neutron depth profiling

Science.gov (United States)

Cetiner, Mustafa Sacit

signal. Without loss of generality, the secondary signal is obtained by the passage of the ion through a thin carbon foil, which produces ion-induced secondary electron emission (IISEE). The time-of-flight spectrometer physically acts as an ion/electron separator. The electrons that enter the active volume of the spectrometer are transported onto the microchannel plate detector to generate the secondary signal. The electron optics can be designed in variety of ways depending on the nature of the measurement and physical requirements. Two ion time-of-flight spectrometer designs are introduced: the parallel electric and magnetic (PEM) field spectrometer and the cross electric and magnetic (CEM) field spectrometer. The CEM field spectrometers have been extensively used in a wide range of applications where precise mass differentiation is required. The PEM field spectrometers have lately found interest in mass spectroscopy applications. The application of the PEM field spectrometer for energy measurements is a novel approach. The PEM field spectrometer used in the measurements employs axial electric and magnetic fields along the nominal direction of the incident ion. The secondary electrons are created by a thin carbon foil on the entrance disk and transported on the microchannel plate that faces the carbon foil. The initial angular distribution of the secondary electrons has virtually no effect on the transport time of the secondary electrons from the surface of the carbon foil to the electron microchannel plate detector. Therefore, the PEM field spectrometer can offer high-resolution energy measurement for relatively lower electric fields. The measurements with the PEM field spectrometer were made with the Tandem linear particle accelerator at the IBM T. J. Watson Research Center at Yorktown Heights, NY. The CEM field spectrometer developed for the thesis employs axial electric field along the nominal direction of the ion, and has perpendicular magnetic field. As the

Capsule Typing of Haemophilus influenzae by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

Science.gov (United States)

Månsson, Viktor; Gilsdorf, Janet R; Kahlmeter, Gunnar; Kilian, Mogens; Kroll, J Simon; Riesbeck, Kristian; Resman, Fredrik

2018-03-01

Encapsulated Haemophilus influenzae strains belong to type-specific genetic lineages. Reliable capsule typing requires PCR, but a more efficient method would be useful. We evaluated capsule typing by using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Isolates of all capsule types (a-f and nontypeable; n = 258) and isogenic capsule transformants (types a-d) were investigated. Principal component and biomarker analyses of mass spectra showed clustering, and mass peaks correlated with capsule type-specific genetic lineages. We used 31 selected isolates to construct a capsule typing database. Validation with the remaining isolates (n = 227) showed 100% sensitivity and 92.2% specificity for encapsulated strains (a-f; n = 61). Blinded validation of a supplemented database (n = 50) using clinical isolates (n = 126) showed 100% sensitivity and 100% specificity for encapsulated strains (b, e, and f; n = 28). MALDI-TOF mass spectrometry is an accurate method for capsule typing of H. influenzae.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry: protocol standardization and database expansion for rapid identification of clinically important molds.

Science.gov (United States)

Paul, Saikat; Singh, Pankaj; Rudramurthy, Shivaprakash M; Chakrabarti, Arunaloke; Ghosh, Anup K

2017-12-01

To standardize the matrix-assisted laser desorption ionization-time of flight mass spectrometry protocols and expansion of existing Bruker Biotyper database for mold identification. Four different sample preparation methods (protocol A, B, C and D) were evaluated. On analyzing each protein extraction method, reliable identification and best log scores were achieved through protocol D. The same protocol was used to identify 153 clinical isolates. Of these 153, 123 (80.3%) were accurately identified by using existing database and remaining 30 (19.7%) were not identified due to unavailability in database. On inclusion of missing main spectrum profile in existing database, all 153 isolates were identified. Matrix-assisted laser desorption ionization-time of flight mass spectrometry can be used for routine identification of clinically important molds.

Development of a broad toxicological screening technique for urine using ultra-performance liquid chromatography and time-of-flight mass spectrometry

DEFF Research Database (Denmark)

Lee, Hon Kit; Ho, Chung Shun; Iu, Yan Ping Heidi

2009-01-01

Withdrawal of the support for the REMEDi HS drug profiling system has necessitated its replacement within our laboratories with an alternative broad toxicological screening technique. To this end, a novel method, based on ultra-performance liquid chromatography (UPLC) and time-of-flight (TOF) mass...

Mass spectrometry with accelerators.

Science.gov (United States)

Litherland, A E; Zhao, X-L; Kieser, W E

2011-01-01

As one in a series of articles on Canadian contributions to mass spectrometry, this review begins with an outline of the history of accelerator mass spectrometry (AMS), noting roles played by researchers at three Canadian AMS laboratories. After a description of the unique features of AMS, three examples, (14)C, (10)Be, and (129)I are given to illustrate the methods. The capabilities of mass spectrometry have been extended by the addition of atomic isobar selection, molecular isobar attenuation, further ion acceleration, followed by ion detection and ion identification at essentially zero dark current or ion flux. This has been accomplished by exploiting the techniques and accelerators of atomic and nuclear physics. In 1939, the first principles of AMS were established using a cyclotron. In 1977 the selection of isobars in the ion source was established when it was shown that the (14)N(-) ion was very unstable, or extremely difficult to create, making a tandem electrostatic accelerator highly suitable for assisting the mass spectrometric measurement of the rare long-lived radioactive isotope (14)C in the environment. This observation, together with the large attenuation of the molecular isobars (13)CH(-) and (12)CH 2(-) during tandem acceleration and the observed very low background contamination from the ion source, was found to facilitate the mass spectrometry of (14)C to at least a level of (14)C/C ~ 6 × 10(-16), the equivalent of a radiocarbon age of 60,000 years. Tandem Accelerator Mass Spectrometry, or AMS, has now made possible the accurate radiocarbon dating of milligram-sized carbon samples by ion counting as well as dating and tracing with many other long-lived radioactive isotopes such as (10)Be, (26)Al, (36)Cl, and (129)I. The difficulty of obtaining large anion currents with low electron affinities and the difficulties of isobar separation, especially for the heavier mass ions, has prompted the use of molecular anions and the search for alternative

Sequencing of Isotope-Labeled Small RNA Using Femtosecond Laser Ablation Time-of-Flight Mass Spectrometry

Science.gov (United States)

Kurata-Nishimura, Mizuki; Ando, Yoshinari; Kobayashi, Tohru; Matsuo, Yukari; Suzuki, Harukazu; Hayashizaki, Yoshihide; Kawai, Jun

2010-04-01

A novel method for the analysis of sequences of small RNAs using nucleotide triphosphates labeled with stable isotopes has been developed using time-of-flight mass spectroscopy combined with femtosecond laser ablation (fsLA-TOF-MS). Small RNAs synthesized with nucleotides enriched in 13C and 15N were efficiently atomized and ionized by single-shot fsLA and the isotope ratios 13C/12C and 15N/14N were evaluated using the TOF-MS method. By comparing the isotope ratios among four different configurations, the number of nucleotide contents of the control RNA sample were successfully reproduced.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a new possibility for the identification and typing of anaerobic bacteria.

Science.gov (United States)

Nagy, Elizabeth

2014-01-01

Anaerobic bacteria predominate in the normal flora of humans and are important, often life-threatening pathogens in mixed infections originating from the indigenous microbiota. The isolation and identification of anaerobes by phenotypic and DNA-based molecular methods at a species level is time-consuming and laborious. Following the successful adaptation of the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the routine laboratory identification of bacteria, the extensive development of a database has been initiated to use this method for the identification of anaerobic bacteria. Not only frequently isolated anaerobic species, but also newly recognized and taxonomically rearranged genera and species can be identified using direct smear samples or whole-cell protein extraction, and even phylogenetically closely related species can be identified correctly by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Typing of anaerobic bacteria on a subspecies level, determination of antibiotic resistance and direct identification of blood culture isolates will revolutionize anaerobe bacteriology in the near future.

Direct mass measurements in the light neutron-rich region using a combined energy and time-of-flight technique

International Nuclear Information System (INIS)

Pillai, C.; Swenson, L.W.; Vieira, D.J.; Butler, G.W.; Wouters, J.M.; Rokni, S.H.; Vaziri, K.; Remsberg, L.P.

1985-01-01

This experiment has demonstrated that direct mass measurements can be performed (albeit of low precision in this first attempt) using the M proportional to ET 2 method. This technique has the advantage that many particle-bound nuclei, produced in fragmentation reactions can be measured simultaneously, independent of their N or Z. The main disadvantage of this approach is that both energy and time-of-flight must be measured precisely on an absolute scale. Although some mass walk with N and Z was observed in this experiment, these uncertainties were largely removed by extrapolating the smooth dependence observed for known nuclei which lie closer to the valley of β-stability. Mass measurements for several neutron-rich light nuclei ranging from 17 C to 26 Ne have been performed. In all cases these measurements agree with the latest mass compilation of Wapstra and Audi. The masses of 20 N and 24 F have been determined for the first time

Analysis of Marine Aerosol Polysaccharides by Pyrolysis Time-of-Flight Mass Spectrometry

Science.gov (United States)

Lawler, M. J.; Grieman, M. M.; Sengur, I.; Saltzman, E. S.

2017-12-01

The relationship between surface ocean biological productivity and marine cloud formation and properties has been explored for decades, but the impacts of marine biogenic emissions on cloudiness and climate remain highly uncertain. This is in part due to the challenge of directly linking biogenic materials in the surface ocean with cloud-forming aerosol. It has been shown that polysaccharide gel-forming materials, also known as transparent exopolymers, may be mechanically ejected from the sea surface during air bubble bursting (Leck and Bigg, 2005). Existing analysis methods for such aerosols require considerable sample mass and sample preparation. As part of the multi-year seasonal North Atlantic Aerosols and Marine Ecosystems Study (NAAMES), ambient submicron marine aerosol was collected in November 2015 and May 2016 from the R/V Atlantis at using a Particle into Liquid Sampler (PILS). These samples of roughly 15 minute time resolution were frozen and returned to UC Irvine for analysis. A new technique has been developed to attempt to quantify polysaccharide material in these ambient samples. A small subsample (1- 5 µL) is taken from the PILS vial samples and allowed to dry on a Pt ribbon filament in the chemical ionization source region of a time-of-flight mass spectrometer. The sample then undergoes a two-step heating process, in which volatilizable molecules are first desorbed and then non-volatilizable large molecules such as polysaccharides are pyrolyzed. These desorbed molecules and decomposition products are ionized using either O2- or H3O+ reagent ion and are directly sampled into the mass spectrometer. The resulting spectra can then be compared to standards of known polysaccharide materials for quantification and potentially structural and/or compositional information.

First spatial separation of a heavy ion isomeric beam with a multiple-reflection time-of-flight mass spectrometer

Science.gov (United States)

Dickel, T.; Plaß, W. R.; Ayet San Andres, S.; Ebert, J.; Geissel, H.; Haettner, E.; Hornung, C.; Miskun, I.; Pietri, S.; Purushothaman, S.; Reiter, M. P.; Rink, A.-K.; Scheidenberger, C.; Weick, H.; Dendooven, P.; Diwisch, M.; Greiner, F.; Heiße, F.; Knöbel, R.; Lippert, W.; Moore, I. D.; Pohjalainen, I.; Prochazka, A.; Ranjan, M.; Takechi, M.; Winfield, J. S.; Xu, X.

2015-05-01

211Po ions in the ground and isomeric states were produced via 238U projectile fragmentation at 1000 MeV/u. The 211Po ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized in a gas-filled cryogenic stopping cell (CSC). They were then extracted from the CSC and injected into a high-resolution multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS). The excitation energy of the isomer and, for the first time, the isomeric-to-ground state ratio were determined from the measured mass spectrum. In the subsequent experimental step, the isomers were spatially separated from the ions in the ground state by an ion deflector and finally collected with a silicon detector for decay spectroscopy. This pioneering experimental result opens up unique perspectives for isomer-resolved studies. With this versatile experimental method new isomers with half-lives longer than a few milliseconds can be discovered and their decay properties can be measured with highest sensitivity and selectivity. These experiments can be extended to studies with isomeric beams in nuclear reactions.

One Hundred False-Positive Amphetamine Specimens Characterized by Liquid Chromatography Time-of-Flight Mass Spectrometry.

Science.gov (United States)

Marin, Stephanie J; Doyle, Kelly; Chang, Annie; Concheiro-Guisan, Marta; Huestis, Marilyn A; Johnson-Davis, Kamisha L

2016-01-01

Some amphetamine (AMP) and ecstacy (MDMA) urine immunoassay (IA) kits are prone to false-positive results due to poor specificity of the antibody. We employed two techniques, high-resolution mass spectrometry (HRMS) and an in silico structure search, to identify compounds likely to cause false-positive results. Hundred false-positive IA specimens for AMP and/or MDMA were analyzed by an Agilent 6230 time-of-flight (TOF) mass spectrometer. Separately, SciFinder (Chemical Abstracts) was used as an in silico structure search to generate a library of compounds that are known to cross-react with AMP/MDMA IAs. Chemical formulas and exact masses of 145 structures were then compared against masses identified by TOF. Compounds known to have cross-reactivity with the IAs were identified in the structure-based search. The chemical formulas and exact masses of 145 structures (of 20 chemical formulas) were compared against masses identified by TOF. Urine analysis by HRMS correlates accurate mass with chemical formulae, but provides little information regarding compound structure. Structural data of targeted antigens can be utilized to correlate HRMS-derived chemical formulas with structural analogs. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Compact Two-step Laser Time-of-Flight Mass Spectrometer for in Situ Analyses of Aromatic Organics on Planetary Missions

Science.gov (United States)

Getty, Stephanie; Brickerhoff, William; Cornish, Timothy; Ecelberger, Scott; Floyd, Melissa

2012-01-01

RATIONALE A miniature time-of-flight mass spectrometer has been adapted to demonstrate two-step laser desorption-ionization (LOI) in a compact instrument package for enhanced organics detection. Two-step LDI decouples the desorption and ionization processes, relative to traditional laser ionization-desorption, in order to produce low-fragmentation conditions for complex organic analytes. Tuning UV ionization laser energy allowed control ofthe degree of fragmentation, which may enable better identification of constituent species. METHODS A reflectron time-of-flight mass spectrometer prototype measuring 20 cm in length was adapted to a two-laser configuration, with IR (1064 nm) desorption followed by UV (266 nm) postionization. A relatively low ion extraction voltage of 5 kV was applied at the sample inlet. Instrument capabilities and performance were demonstrated with analysis of a model polycyclic aromatic hydrocarbon, representing a class of compounds important to the fields of Earth and planetary science. RESULTS L2MS analysis of a model PAH standard, pyrene, has been demonstrated, including parent mass identification and the onset o(tunable fragmentation as a function of ionizing laser energy. Mass resolution m/llm = 380 at full width at half-maximum was achieved which is notable for gas-phase ionization of desorbed neutrals in a highly-compact mass analyzer. CONCLUSIONS Achieving two-step laser mass spectrometry (L2MS) in a highly-miniature instrument enables a powerful approach to the detection and characterization of aromatic organics in remote terrestrial and planetary applications. Tunable detection of parent and fragment ions with high mass resolution, diagnostic of molecular structure, is possible on such a compact L2MS instrument. Selectivity of L2MS against low-mass inorganic salt interferences is a key advantage when working with unprocessed, natural samples, and a mechanism for the observed selectivity is presented.

Identification of barley and rye varieties using matrix- assisted laser desorption/ionisation time-of-flight mass spectrometry with neural networks

DEFF Research Database (Denmark)

Bloch, H.A.; Petersen, Marianne Kjerstine; Sperotto, Maria Maddalena

2001-01-01

developed, which combines analysis of alcohol-soluble wheat proteins (gliadins) using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry with neural networks. Here we have applied the same method for the identification of both barley (Hordeum vulgare L.) and rye (Secale cereale L.......) varieties. For barley, 95% of the mass spectra were correctly classified. This is an encouraging result, since in earlier experiments only a grouping into subsets of varieties was possible. However, the method was not useful in the classification of rye, due to the strong similarity between mass spectra...

Discretization of space and time: mass-energy relation, accelerating expansion of the Universe, Hubble constant

OpenAIRE

Roatta , Luca

2017-01-01

Assuming that space and time can only have discrete values, we obtain the expression of the gravitational potential energy that at large distance coincides with the Newtonian. In very precise circumstances it coincides with the relativistic mass-energy relation: this shows that the Universe is a black hole in which all bodies are subjected to an acceleration toward the border of the Universe itself. Since the Universe is a black hole with a fixed radius, we can obtain the density of the Unive...

Installation of a tandem-type accelerator mass spectrometer

International Nuclear Information System (INIS)

Mizushima, Toshihiko; Togawa, Orihiko; Mizutani, Yoshihiko; Yamamoto, Tadatoshi

2000-02-01

Tandem-type accelerator mass spectrometer (hereinafter referred to as Tandetron) was installed at the Ominato Facility of Mutsu Establishment, JAERI in April, 1997. The objective of its installation is to investigate the mechanism of the mixing and circulation of seawater in the ocean, by collecting seawater samples around Japan and analyzing the horizontal and vertical distributions of 14 C contained in the samples. The Tandetron consists of two lines to measure isotopic ratios of carbon and those of heavier iodine. The adjustment for the carbon line was finished and the measurements of seawater samples were started. The iodine line, on the other hand, is on the final step of its adjustment and performance tests are being carried out with a TOF (Time of Flight) detector. The iodine line will be used to analyze 129 I released from a spent nuclear fuel reprocessing plant and other nuclear facilities. In this report, we summarize the status of installation of the carbon and iodine lines for the Tandetron. The report describes the situations of their adjustments until now, the outline of the Tandetron, tests of measurement performance, evaluation and inspection of shielding performance, problems and their solutions, and so on. (author)

Analysis of carbohydrates in Fusarium verticillioides using size-exclusion HPLC – DRI and direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS)

Science.gov (United States)

Direct analysis in real time ionization – time-of-flight – mass spectrometry (DART-MS) and size-exclusion HPLC – DRI are used, respectively, to qualitatively and quantitatively determine the carbohydrates extracted from the corn rot fungus Fusarium verticillioides. In situ permethylation in the DART...

Comprehensive Two-dimensional Liquid Chromatography coupled to High Resolution Time of Flight Mass Spectrometry for Chemical Characterization of Sewage Treatment Plant Effluents

NARCIS (Netherlands)

Ouyang, X.; Leonards, P.E.G.; Legler, J.; van der Oost, R.; de Boer, J.; Lamoree, M.H.

2015-01-01

For the first time a comprehensive two-dimensional liquid chromatography (LC. ×. LC) system coupled with a high resolution time-of-flight mass spectrometer (HR-ToF MS) was developed and applied for analysis of emerging toxicants in wastewater effluent. The system was optimized and validated using

A GPU Accelerated Spring Mass System for Surgical Simulation

DEFF Research Database (Denmark)

Mosegaard, Jesper; Sørensen, Thomas Sangild

2005-01-01

There is a growing demand for surgical simulators to dofast and precise calculations of tissue deformation to simulateincreasingly complex morphology in real-time. Unfortunately, evenfast spring-mass based systems have slow convergence rates for largemodels. This paper presents a method to accele...... to accelerate computation of aspring-mass system in order to simulate a complex organ such as theheart. This acceleration is achieved by taking advantage of moderngraphics processing units (GPU)....

An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies

International Nuclear Information System (INIS)

Schowalter, Steven J.; Chen Kuang; Rellergert, Wade G.; Sullivan, Scott T.; Hudson, Eric R.

2012-01-01

We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates.

Perception of tilt (somatogravic illusion) in response to sustained linear acceleration during space flight

Science.gov (United States)

Clement, G.; Moore, S. T.; Raphan, T.; Cohen, B.

2001-01-01

During the 1998 Neurolab mission (STS-90), four astronauts were exposed to interaural and head vertical (dorsoventral) linear accelerations of 0.5 g and 1 g during constant velocity rotation on a centrifuge, both on Earth and during orbital space flight. Subjects were oriented either left-ear-out or right-ear-out (Gy centrifugation), or lay supine along the centrifuge arm with their head off-axis (Gz centrifugation). Pre-flight centrifugation, producing linear accelerations of 0.5 g and 1 g along the Gy (interaural) axis, induced illusions of roll-tilt of 20 degrees and 34 degrees for gravito-inertial acceleration (GIA) vector tilts of 27 degrees and 45 degrees , respectively. Pre-flight 0.5 g and 1 g Gz (head dorsoventral) centrifugation generated perceptions of backward pitch of 5 degrees and 15 degrees , respectively. In the absence of gravity during space flight, the same centrifugation generated a GIA that was equivalent to the centripetal acceleration and aligned with the Gy or Gz axes. Perception of tilt was underestimated relative to this new GIA orientation during early in-flight Gy centrifugation, but was close to the GIA after 16 days in orbit, when subjects reported that they felt as if they were 'lying on side'. During the course of the mission, inflight roll-tilt perception during Gy centrifugation increased from 45 degrees to 83 degrees at 1 g and from 42 degrees to 48 degrees at 0.5 g. Subjects felt 'upside-down' during in-flight Gz centrifugation from the first in-flight test session, which reflected the new GIA orientation along the head dorsoventral axis. The different levels of in-flight tilt perception during 0.5 g and 1 g Gy centrifugation suggests that other non-vestibular inputs, including an internal estimate of the body vertical and somatic sensation, were utilized in generating tilt perception. Interpretation of data by a weighted sum of body vertical and somatic vectors, with an estimate of the GIA from the otoliths, suggests that

Acceleration of microparticle

CERN Document Server

Shibata, H

2002-01-01

A microparticle (dust) ion source has been installed at the high voltage terminal of the 3.75 MV single ended Van de Graaff electrostatic accelerator and a beam line for microparticle experiments has been build at High Fluence Irradiation Facility (HIT) of Research Center for Nuclear Science and Technology, the University of Tokyo. Microparticle acceleration has been successful in obtaining expected velocities of 1-20 km/s or more for micron or submicron sized particles. Development of in situ dust detectors and analyzers on board satellites and spacecraft in the expected mass and velocity range of micrometeoroids and investigation of hypervelocity impact phenomena by using time of flight mass spectrometry, impact flash or luminescence measurement and scanning electron or laser microscope observation for metals, ceramics, polymers and semiconductors bombarded by micron-sized particles were started three years ago. (author)

Symposium on accelerator mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

None

1981-01-01

The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

Symposium on accelerator mass spectrometry

International Nuclear Information System (INIS)

1981-01-01

The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base

Accurate Mass GC/LC-Quadrupole Time of Flight Mass Spectrometry Analysis of Fatty Acids and Triacylglycerols of Spicy Fruits from the Apiaceae Family

Directory of Open Access Journals (Sweden)

Thao Nguyen

2015-12-01

Full Text Available The triacylglycerol (TAG structure and the regio-stereospecific distribution of fatty acids (FA of seed oils from most of the Apiaceae family are not well documented. The TAG structure ultimately determines the final physical properties of the oils and the position of FAs in the TAG molecule affects the digestion; absorption and metabolism; and physical and technological properties of TAGs. Fixed oils from the fruits of dill (Anethum graveolens, caraway (Carum carvi, cumin (Cuminum cyminum, coriander (Coriandrum sativum, anise (Pimpinella anisum, carrot (Daucus carota, celery (Apium graveolens, fennel (Foeniculum vulgare, and Khella (Ammi visnaga, all from the Apiaceae family, were extracted at room temperature in chloroform/methanol (2:1 v/v using percolators. Crude lipids were fractionated by solid phase extraction to separate neutral triacylglycerols (TAGs from other lipids components. Neutral TAGs were subjected to transesterification process to convert them to their corresponding fatty acids methyl esters (FAMES using 1% boron trifluoride (BF3 in methanol. FAMES were analyzed by gas chromatography-quadrupole time of flight (GC-QTOF mass spectrometry. Triglycerides were analyzed using high performance liquid chromatography-quadrupole time of flight (LC-QTOF mass spectrometry. Petroselinic acid was the major fatty acid in all samples ranging from 57% of the total fatty acids in caraway up to 82% in fennel. All samples contained palmitic (16:0, palmitoleic (C16:1n-9, stearic (C18:0, petroselinic (C18:1n-12, linoleic (C18:2n-6, linolinic (18:3n-3, and arachidic (C20:0 acids. TAG were analyzed using LC-QTOF for accurate mass identification and mass spectrometry/mass spectrometry (MS/MS techniques for regiospesific elucidation of the identified TAGs. Five major TAGs were detected in all samples but with different relative concentrations in all of the tested samples. Several other TAGs were detected as minor components and were present in some

Determination of the Isotope Ratio for Metal Samples Using a Laser Ablation/Ionization Time-of-flight Mass Spectrometry

International Nuclear Information System (INIS)

Song, Kyu Seok; Cha, Hyung Ki; Kim, Duk Hyeon; Min, Ki Hyun

2004-01-01

The laser ablation/ionization time-of-flight mass spectrometry is applied to the isotopic analysis of solid samples using a home-made instrument. The technique is convenient for solid sample analysis due to the onestep process of vaporization and ionization of the samples. The analyzed samples were lead, cadmium, molybdenum, and ytterbium. To optimize the analytical conditions of the technique, several parameters, such as laser energy, laser wavelength, size of the laser beam on the samples surface, and high voltages applied on the ion source electrodes were varied. Low energy of laser light was necessary to obtain the optimal mass resolution of spectra. The 532 nm light generated mass spectra with the higher signal-to-noise ratio compared with the 355 nm light. The best mass resolution obtained in the present study is ∼1,500 for the ytterbium

X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry characterization of aging effects on the mineral fibers treated with aminopropylsilane and quaternary ammonium compounds

DEFF Research Database (Denmark)

Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.

2012-01-01

(PCA) was applied to the time-of-flight secondary ion mass spectrometry spectra, and an increase in the intensities of APS characteristic peaks were observed after aging. The observed increase in the signals of APS originates from underlying silanized fibers after the removal of the surfactant......X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry were used to investigate the aging effects on the aminopropylsilane (APS) and quaternary ammonium surfactant-treated mineral fibers. APS-coated mineral fiber samples were treated with cationic surfactant...

Applications of accelerator mass spectrometry: advances and innovation

International Nuclear Information System (INIS)

Fifield, L.K.

2004-01-01

Emerging trends in the applications of accelerator mass spectrometry (AMS) are identified and illustrated with specific examples. Areas of application covered include rapid landscape evolution, calibration of the radiocarbon time scale, compound-specific radiocarbon studies, tracing of nuclear discharges, and searches for extraterrestrial isotopes

An integrated ion trap and time-of-flight mass spectrometer for chemical and photo- reaction dynamics studies.

Science.gov (United States)

Schowalter, Steven J; Chen, Kuang; Rellergert, Wade G; Sullivan, Scott T; Hudson, Eric R

2012-04-01

We demonstrate the integration of a linear quadrupole trap with a simple time-of-flight mass spectrometer with medium-mass resolution (m/Δm ∼ 50) geared towards the demands of atomic, molecular, and chemical physics experiments. By utilizing a novel radial ion extraction scheme from the linear quadrupole trap into the mass analyzer, a device with large trap capacity and high optical access is realized without sacrificing mass resolution. This provides the ability to address trapped ions with laser light and facilitates interactions with neutral background gases prior to analyzing the trapped ions. Here, we describe the construction and implementation of the device as well as present representative ToF spectra. We conclude by demonstrating the flexibility of the device with proof-of-principle experiments that include the observation of molecular-ion photodissociation and the measurement of trapped-ion chemical reaction rates. © 2012 American Institute of Physics

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...

A Time-of-Flight System for Low Energy Charged Particles

Science.gov (United States)

Giordano, Micheal; Sadwick, Krystalyn; Fletcher, Kurt; Padalino, Stephen

2013-10-01

A time-of-flight system has been developed to measure the energy of charged particles in the keV range. Positively charged ions passing through very thin carbon films mounted on grids generate secondary electrons. These electrons are accelerated by a -2000 V grid bias towards a grounded channeltron electron multiplier (CEM) which amplifies the signal. Two CEM detector assemblies are mounted 23.1 cm apart along the path of the ions. An ion generates a start signal by passing through the first CEM and a stop signal by passing through the second. The start and stop signals generate a time-of-flight spectrum via conventional electronics. Higher energy alpha particles from radioactive sources have been used to test the system. This time-of-flight system will be deployed to measure the energies of 15 to 30 keV ions produced by a duoplasmatron ion source that is used to characterize ICF detectors.

The ARGUS time-of-flight system

International Nuclear Information System (INIS)

Heller, R.; Klinger, T.; Salomon, R.; Schubert, K.R.; Stiewe, J.; Waldi, R.; Weseler, S.

1985-01-01

The time-of-flight system of the ARGUS detector at the DORIS e + e - storage ring consists of 64 barrel scintillation counters covering 75% of 4π, and 2x48 end cap counters, covering 17% of 4π. The barrel counters are viewed by two phototubes each, while the end cap counters have one tube only. The time-of-flight system serves as a part of the fast trigger and identifies charged particles. The time resolution achieved during the first year of ARGUS operation is 210 ps for Bhabhas (which are used for the off-line monitoring of the system), and 220 ps for hadrons, both in barrel and end cap counters. This converts into a three standard deviation mass separation up to 700 MeV/c between pions and kaons and 1200 MeV/c between kaons and protons. Electrons can be separated from heavier particles up to 230 MeV/c. (orig.)

Metabolic profiling of Hoodia, Chamomile, Terminalia Species and evaluation of commercial preparations using Ultra-High Performance Quadrupole Time of Flight-Mass Spectrometry

Science.gov (United States)

Ultra-High Performance-Quadrupole Time of Flight Mass Spectrometr(UHPLC-QToF-MS)profiling has become an impattant tool for identification of marker compounds and generation of metabolic patterns that could be interrogated using chemometric modeling software. Chemometric approaches can be used to ana...

Time-of-flight techniques applied to neutron spectra measurements in fast subcritical assemblies

International Nuclear Information System (INIS)

Rotival, Michel

1975-04-01

Time-of-flight measurements on Uranium-Graphite assemblies were performed using the BCMN linear accelerator. Methods to provide scalar spectra averaged over a core cell from these experimental results are described [fr

Comprehensive two-dimensional liquid chromatography–time-of-flight mass spectrometry in the analysis of acidic compounds in atmospheric aerosols

Czech Academy of Sciences Publication Activity Database

Pól, Jaroslav; Hohnová, B.; Jussila, M.; Hyötyläinen, T.

2006-01-01

Roč. 1130, č. 1 (2006), s. 64-71 ISSN 0021-9673. [International Symposium on Hyphenated Techniques in Chromatography and Hyphenated Chromatographic Analyzers /9./. York, 08.02.2006-10.02.2006] Institutional research plan: CEZ:AV0Z40310501 Keywords : comprehensive two-dimensional liquid chromatography * time-of-flight mass spectrometry * atmospheric aerosol analysis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.554, year: 2006

Hydrogen atom scrambling in selectively labeled anionic peptides upon collisional activation by MALDI tandem time-of-flight mass spectrometry

DEFF Research Database (Denmark)

Bache, Nicolai; Rand, Kasper Dyrberg; Roepstorff, Peter

2008-01-01

have now measured the level of hydrogen scrambling in a deprotonated, selectively labeled peptide using MALDI tandem time-of-flight mass spectrometry. Our results conclusively show that hydrogen scrambling is prevalent in the deprotonated peptide upon collisional activation. The amide hydrogens ((1)H....../(2)H) have migrated extensively in the anionic peptide, thereby erasing the original regioselective deuteration pattern obtained in solution....

A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

Science.gov (United States)

Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

2018-02-01

A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

Laser ablation synthesis of arsenic-phosphide Asm Pn clusters from As-P mixtures. Laser desorption ionisation with quadrupole ion trap time-of-flight mass spectrometry: The mass spectrometer as a synthesizer.

Science.gov (United States)

Kubáček, Pavel; Prokeš, Lubomír; Pamreddy, Annapurna; Peña-Méndez, Eladia María; Conde, José Elias; Alberti, Milan; Havel, Josef

2018-05-30

Only a few arsenic phosphides are known. A high potential for the generation of new compounds is offered by Laser Ablation Synthesis (LAS) and when Laser Desorption Ionization (LDI) is coupled with simultaneous Time-Of-Flight Mass Spectrometry (TOFMS), immediate identification of the clusters can be achieved. LAS was used for the generation of arsenic phosphides via laser ablation of phosphorus-arsenic mixtures while quadrupole ion trap time-of-flight mass spectrometry (QIT-TOFMS) was used to acquire the mass spectra. Many new As m P n ± clusters (479 binary and 369 mono-elemental) not yet described in the literature were generated in the gas phase and their stoichiometry determined. The likely structures for some of the observed clusters arbitrary selected (20) were computed by density functional theory (DFT) optimization. LAS is an advantageous approach for the generation of new As m P n clusters, while mass spectrometry was found to be an efficient technique for the determination of cluster stoichiometry. The results achieved might inspire the synthesis of new materials. Copyright © 2018 John Wiley & Sons, Ltd.

Monoacylglycerol Analysis Using MS/MSALL Quadruple Time of Flight Mass Spectrometry

Directory of Open Access Journals (Sweden)

Fei Gao

2016-08-01

Full Text Available Monoacylglycerols (MAGs are structural and bioactive metabolites critical for biological function. Development of facile tools for measuring MAG are essential to understand its role in different diseases and various pathways. A data-independent acquisition method, MS/MSALL, using electrospray ionization (ESI coupled quadrupole time of flight mass spectrometry (MS, was utilized for the structural identification and quantitative analysis of individual MAG molecular species. Compared with other acylglycerols, diacylglycerols (DAG and triacylglycerols (TAG, MAG characteristically presented as a dominant protonated ion, [M + H]+, and under low collision energy as fatty acid-like fragments due to the neutral loss of the glycerol head group. At low concentrations (<10 pmol/µL, where lipid-lipid interactions are rare, there was a strong linear correlation between ion abundance and MAG concentration. Moreover, using the MS/MSALL method the major MAG species from human plasma and mouse brown and white adipose tissues were quantified in less than 6 min. Collectively, these results demonstrate that MS/MSALL analysis of MAG is an enabling strategy for the direct identification and quantitative analysis of low level MAG species from biological samples with high throughput and sensitivity.

Chemical discrimination of lubricant marketing types using direct analysis in real time time-of-flight mass spectrometry.

Science.gov (United States)

Maric, Mark; Harvey, Lauren; Tomcsak, Maren; Solano, Angelique; Bridge, Candice

2017-06-30

In comparison to other violent crimes, sexual assaults suffer from very low prosecution and conviction rates especially in the absence of DNA evidence. As a result, the forensic community needs to utilize other forms of trace contact evidence, like lubricant evidence, in order to provide a link between the victim and the assailant. In this study, 90 personal bottled and condom lubricants from the three main marketing types, silicone-based, water-based and condoms, were characterized by direct analysis in real time time of flight mass spectrometry (DART-TOFMS). The instrumental data was analyzed by multivariate statistics including hierarchal cluster analysis, principal component analysis, and linear discriminant analysis. By interpreting the mass spectral data with multivariate statistics, 12 discrete groupings were identified, indicating inherent chemical diversity not only between but within the three main marketing groups. A number of unique chemical markers, both major and minor, were identified, other than the three main chemical components (i.e. PEG, PDMS and nonoxynol-9) currently used for lubricant classification. The data was validated by a stratified 20% withheld cross-validation which demonstrated that there was minimal overlap between the groupings. Based on the groupings identified and unique features of each group, a highly discriminating statistical model was then developed that aims to provide the foundation for the development of a forensic lubricant database that may eventually be applied to casework. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Fast screening and quantitation of microcystins in microalgae dietary supplement products and water by liquid chromatography coupled to time of flight mass spectrometry

International Nuclear Information System (INIS)

Ortelli, Didier; Edder, Patrick; Cognard, Emmanuelle; Jan, Philippe

2008-01-01

Cyanobacteria, commonly called 'blue-green algae', may accumulate in surface water supplies as 'blooms' and may concentrate on the surface as blue-green 'scums'. Some species of cyanobacteria produce toxins and are of relevance to water supplies and to microalgae dietary supplements. To ensure the safety of drinking water and blue-green algae products, analyses are the only way to determine the presence or absence of toxins. This paper shows the use of ultra performance liquid chromatography (UPLC) coupled to orthogonal acceleration time of flight (TOF) mass spectrometry for the detection and quantitation of microcystins. The method presented is very sensitive, simple, fast, robust and did not require fastidious clean-up step. Limits of detection of 0.1 μg L -1 in water and 0.1-0.2 μg g -1 in microalgae samples were achieved. Method performances were satisfactory and appropriate for monitoring of water and dietary supplements. The method was applied in routine to samples taken from Swiss market or buy on internet website. Among 19 samples, six showed the presence of microcystins LR and LA at harmful levels

High mass resolution, high angular acceptance time-of-flight mass spectroscopy for planetary missions under the Planetary Instrument Definition and Development Program (PIDDP)

Science.gov (United States)

Young, David T.

1991-01-01

This final report covers three years and several phases of work in which instrumentation for the Planetary Instrument Definition and Development Program (PIDDP) were successfully developed. There were two main thrusts to this research: (1) to develop and test methods for electrostatically scanning detector field-of-views, and (2) to improve the mass resolution of plasma mass spectrometers to M/delta M approximately 25, their field-of-view (FOV) to 360 degrees, and their E-range to cover approximately 1 eV to 50 keV. Prototypes of two different approaches to electrostatic scanning were built and tested. The Isochronous time-of-flight (TOF) and the linear electric field 3D TOF devices were examined.

Surface Mass Balance Contributions to Acceleration of Antarctic Ice Mass Loss during 2003- 2013

Science.gov (United States)

Seo, K. W.; Wilson, C. R.; Scambos, T. A.; Kim, B. M.; Waliser, D. E.; Tian, B.; Kim, B.; Eom, J.

2015-12-01

Recent observations from satellite gravimetry (the GRACE mission) suggest an acceleration of ice mass loss from the Antarctic Ice Sheet (AIS). The contribution of surface mass balance changes (due to variable precipitation) is compared with GRACE-derived mass loss acceleration by assessing the estimated contribution of snow mass from meteorological reanalysis data. We find that over much of the continent, the acceleration can be explained by precipitation anomalies. However, on the Antarctic Peninsula and other parts of West Antarctica mass changes are not explained by precipitation and are likely associated with ice discharge rate increases. The total apparent GRACE acceleration over all of the AIS between 2003 and 2013 is -13.6±7.2 GTon/yr2. Of this total, we find that the surface mass balance component is -8.2±2.0 GTon/yr2. However, the GRACE estimate appears to contain errors arising from the atmospheric pressure fields used to remove air mass effects. The estimated acceleration error from this effect is about 9.8±5.8 GTon/yr2. Correcting for this yields an ice discharge acceleration of -15.1±6.5 GTon/yr2.

Identification and classification of components in flash pyrolysis oil and hydrodeoxygenated oils by two-dimensional gas chromatography and time-of-flight mass spectrometry

NARCIS (Netherlands)

Marsman, J. H.; Wildschut, J.; Evers, P.; Heeres, H. J.; Koning de, S.

2008-01-01

Hydrodeoxygenated pyrolysis oils (HDO) are considered promising renewable liquid energy carriers. To gain insights in the various reaction pathways taking place during the hydrodeoxygenation reaction of pyrolysis oil, two-dimensional gas chromatography with time-of-flight mass spectrometric analyses

Precision measurements with the multi-reflection time-of-flight mass spectrometer of ISOLTRAP at ISOLDE/CERN

Energy Technology Data Exchange (ETDEWEB)

Atanasov, Dinko; Ascher, Pauline; Borgmann, Christopher; Boehm, Christine; Eliseev, Sergey; Eronen, Tommi; George, Sebastian; Kisler, Dmitry; Naimi, Sarah [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Beck, Dietrich; Herfurth, Frank; Litvinov, Yuri; Minaya Ramirez, Enrique; Neidherr, Dennis [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstr. 1, 64291 Darmstadt (Germany); Breitenfeldt, Martin [Instituut voor Kern- en Stralingsfysica, Celestijnenlaan 200d - bus 2418, 3001 Heverlee (Belgium); Cakirli, Burcu [University of Istanbul, Department of Physics, 34134 Istanbul (Turkey); Cocolios, Thomas Elias [University of Manchester, Manchester (United Kingdom); Herlert, Alexander Josef [FAIR GmbH, Planckstr. 1, D-64291 Darmstadt (Germany); Kowalska, Magdalena [CERN, Geneva 23, 1211 Geneva (Switzerland); Kreim, Susanne [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); CERN, Geneva 23, 1211 Geneva (Switzerland); Lunney, David; Manea, Vladimir [CSNSM-IN2P3-CNRS, 91405 Orsay Campus, Bat. 104, 108 (France); Rosenbusch, Marco; Schweikhard, Lutz; Wienholtz, Frank; Wolf, Robert [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, Felix-Hausdorff-Str. 6, 17487 Greifswald (Germany); Stanja, Juliane; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, Technische Universitaet Dresden, Zellescher Weg 19, 01069 Dresden (Germany)

2014-07-01

The masses of exotic nuclides are among the most important input parameters for modern nuclear theory and astrophysical models. At the high-precision Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN, a multi-reflection time-of-flight mass spectrometer (MR-ToF-MS) in combination with a Bradbury-Nielsen gate (BNG) can be used to achieve high-resolution isobar purification with mass-resolving powers of 105 in a few tens of milliseconds. Furthermore, the MR-ToF device can be used as a spectrometer to determine the masses of nuclides with very low yields and short half-lives, where a Penning-trap mass measurement becomes impractical due to the lower transport efficiency and decay losses during the purification and measurement cycles. Recent cross-check experiments show that the MR-ToF MS allows mass measurements with uncertainties in the sub-ppm range. In a first application the mass measurements of the nuclides 53,54Ca was performed, delivered with production rates as low as 10/s and half-lives of only 90(6) ms. The nuclides serve as important benchmarks for testing modern chiral effective theory with realistic 3-body forces. The contribution presents the on-line mass spectrometer ISOLTRAP focusing on the new applications, which became possible after the implementation of the MR-ToF MS into the current setup. In particular, the mass measurements of the neutron-rich calcium isotopes up to A=54 are discussed. In addition, measurements of the isotonic potassium isotopes are reported.

Accelerator mass spectrometry.

Science.gov (United States)

Hellborg, Ragnar; Skog, Göran

2008-01-01

In this overview the technique of accelerator mass spectrometry (AMS) and its use are described. AMS is a highly sensitive method of counting atoms. It is used to detect very low concentrations of natural isotopic abundances (typically in the range between 10(-12) and 10(-16)) of both radionuclides and stable nuclides. The main advantages of AMS compared to conventional radiometric methods are the use of smaller samples (mg and even sub-mg size) and shorter measuring times (less than 1 hr). The equipment used for AMS is almost exclusively based on the electrostatic tandem accelerator, although some of the newest systems are based on a slightly different principle. Dedicated accelerators as well as older "nuclear physics machines" can be found in the 80 or so AMS laboratories in existence today. The most widely used isotope studied with AMS is 14C. Besides radiocarbon dating this isotope is used in climate studies, biomedicine applications and many other fields. More than 100,000 14C samples are measured per year. Other isotopes studied include 10Be, 26Al, 36Cl, 41Ca, 59Ni, 129I, U, and Pu. Although these measurements are important, the number of samples of these other isotopes measured each year is estimated to be less than 10% of the number of 14C samples. Copyright 2008 Wiley Periodicals, Inc.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry for direct bacterial identification from positive blood culture pellets.

Science.gov (United States)

Prod'hom, Guy; Bizzini, Alain; Durussel, Christian; Bille, Jacques; Greub, Gilbert

2010-04-01

An ammonium chloride erythrocyte-lysing procedure was used to prepare a bacterial pellet from positive blood cultures for direct matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry analysis. Identification was obtained for 78.7% of the pellets tested. Moreover, 99% of the MALDI-TOF identifications were congruent at the species level when considering valid scores. This fast and accurate method is promising.

Surface mass balance contributions to acceleration of Antarctic ice mass loss during 2003-2013

OpenAIRE

Seo, Ki-Weon; Wilson, Clark R.; Scambos, Ted; Kim, Baek-Min; Waliser, Duane E.; Tian, Baijun; Kim, Byeong-Hoon; Eom, Jooyoung

2015-01-01

Abstract Recent observations from satellite gravimetry (the Gravity Recovery and Climate Experiment (GRACE) mission) suggest an acceleration of ice mass loss from the Antarctic Ice Sheet (AIS). The contribution of surface mass balance changes (due to variable precipitation) is compared with GRACE?derived mass loss acceleration by assessing the estimated contribution of snow mass from meteorological reanalysis data. We find that over much of the continent, the acceleration can be explained by ...

Effective Acceleration Model for the Arrival Time of Interplanetary Shocks driven by Coronal Mass Ejections

Science.gov (United States)

Paouris, Evangelos; Mavromichalaki, Helen

2017-12-01

In a previous work (Paouris and Mavromichalaki in Solar Phys. 292, 30, 2017), we presented a total of 266 interplanetary coronal mass ejections (ICMEs) with as much information as possible. We developed a new empirical model for estimating the acceleration of these events in the interplanetary medium from this analysis. In this work, we present a new approach on the effective acceleration model (EAM) for predicting the arrival time of the shock that preceds a CME, using data of a total of 214 ICMEs. For the first time, the projection effects of the linear speed of CMEs are taken into account in this empirical model, which significantly improves the prediction of the arrival time of the shock. In particular, the mean value of the time difference between the observed time of the shock and the predicted time was equal to +3.03 hours with a mean absolute error (MAE) of 18.58 hours and a root mean squared error (RMSE) of 22.47 hours. After the improvement of this model, the mean value of the time difference is decreased to -0.28 hours with an MAE of 17.65 hours and an RMSE of 21.55 hours. This improved version was applied to a set of three recent Earth-directed CMEs reported in May, June, and July of 2017, and we compare our results with the values predicted by other related models.

Computer automation of an accelerator mass spectrometry system

International Nuclear Information System (INIS)

Gressett, J.D.; Maxson, D.L.; Matteson, S.; McDaniel, F.D.; Duggan, J.L.; Mackey, H.J.; North Texas State Univ., Denton, TX; Anthony, J.M.

1989-01-01

The determination of trace impurities in electronic materials using accelerator mass spectrometry (AMS) requires efficient automation of the beam transport and mass discrimination hardware. The ability to choose between a variety of charge states, isotopes and injected molecules is necessary to provide survey capabilities similar to that available on conventional mass spectrometers. This paper will discuss automation hardware and software for flexible, high-sensitivity trace analysis of electronic materials, e.g. Si, GaAs and HgCdTe. Details regarding settling times will be presented, along with proof-of-principle experimental data. Potential and present applications will also be discussed. (orig.)

A time of flight detector for high energy heavy particles

Energy Technology Data Exchange (ETDEWEB)

Fang, Z.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

1993-12-31

As a commonly used method to measure the energy of a particle with known mass, the flight time of the particle travelling over a certain distance is measured. A detector based on this principle is called a time-of-flight (TOF) detector which has attracted interests constantly during the last 15 years. For high energy heavy particle energy detection, TOF detector is an appropriated choice and such a system, developed recently, is described in this paper. 8 refs., 3 figs.

A time of flight detector for high energy heavy particles

Energy Technology Data Exchange (ETDEWEB)

Fang, Z; O` Connor, D J [Newcastle Univ., NSW (Australia). Dept. of Physics

1994-12-31

As a commonly used method to measure the energy of a particle with known mass, the flight time of the particle travelling over a certain distance is measured. A detector based on this principle is called a time-of-flight (TOF) detector which has attracted interests constantly during the last 15 years. For high energy heavy particle energy detection, TOF detector is an appropriated choice and such a system, developed recently, is described in this paper. 8 refs., 3 figs.

Time series analysis methods and applications for flight data

CERN Document Server

Zhang, Jianye

2017-01-01

This book focuses on different facets of flight data analysis, including the basic goals, methods, and implementation techniques. As mass flight data possesses the typical characteristics of time series, the time series analysis methods and their application for flight data have been illustrated from several aspects, such as data filtering, data extension, feature optimization, similarity search, trend monitoring, fault diagnosis, and parameter prediction, etc. An intelligent information-processing platform for flight data has been established to assist in aircraft condition monitoring, training evaluation and scientific maintenance. The book will serve as a reference resource for people working in aviation management and maintenance, as well as researchers and engineers in the fields of data analysis and data mining.

Dual Source Time-of-flight Mass Spectrometer and Sample Handling System

Science.gov (United States)

Brinckerhoff, W.; Mahaffy, P.; Cornish, T.; Cheng, A.; Gorevan, S.; Niemann, H.; Harpold, D.; Rafeek, S.; Yucht, D.

We present details of an instrument under development for potential NASA missions to planets and small bodies. The instrument comprises a dual ionization source (laser and electron impact) time-of-flight mass spectrometer (TOF-MS) and a carousel sam- ple handling system for in situ analysis of solid materials acquired by, e.g., a coring drill. This DSTOF instrument could be deployed on a fixed lander or a rover, and has an open design that would accommodate measurements by additional instruments. The sample handling system (SHS) is based on a multi-well carousel, originally de- signed for Champollion/DS4. Solid samples, in the form of drill cores or as loose chips or fines, are inserted through an access port, sealed in vacuum, and transported around the carousel to a pyrolysis cell and/or directly to the TOF-MS inlet. Samples at the TOF-MS inlet are xy-addressable for laser or optical microprobe. Cups may be ejected from their holders for analyzing multiple samples or caching them for return. Samples are analyzed with laser desorption and evolved-gas/electron-impact sources. The dual ion source permits studies of elemental, isotopic, and molecular composition of unprepared samples with a single mass spectrometer. Pulsed laser desorption per- mits the measurement of abundance and isotope ratios of refractory elements, as well as the detection of high-mass organic molecules in solid samples. Evolved gas analysis permits similar measurements of the more volatile species in solids and aerosols. The TOF-MS is based on previous miniature prototypes at JHU/APL that feature high sensitivity and a wide mass range. The laser mode, in which the sample cup is directly below the TOF-MS inlet, permits both ablation and desorption measurements, to cover elemental and molecular species, respectively. In the evolved gas mode, sample cups are raised into a small pyrolysis cell and heated, producing a neutral gas that is elec- tron ionized and pulsed into the TOF-MS. (Any imaging

Storage ion trap of an 'In-Flight Capture' type for precise mass measurement of radioactive nuclear reaction products and fission fragments

International Nuclear Information System (INIS)

Tarantin, N.I.

2001-01-01

Data on nuclear masses provide a basis for creating and testing various nuclear models. A tandem system of FLNR comprised of the U-400M cyclotron, the COMBAS magnetic separator and the mass-spectrometric ion trap of an 'in-flight capture' type is considered as a possible complex for producing of the short-lived nuclei in fragmentation reactions by heavy ions and for precise mass measurement of these nuclei. The plan of scientific and technical FLNR research includes a project DRIBs for producing beams of accelerated radioactive nuclear reaction products and photofission fragments. This project proposes also precise mass measurements of the fission fragment with the help of the ion trap. The in-flight entrance of the ions and their capture in the mass-spectrometric ion trap using the monochromatizing degrader, the static electric and magnetic fields and a new invention, a magnetic unidirectional transporting ventil, is considered

Reduction of the jitter of single-flux-quantum time-to-digital converters for time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Sano, K.; Muramatsu, Y.; Yamanashi, Y.; Yoshikawa, N.; Zen, N.; Ohkubo, M.

2014-01-01

Highlights: • We proposed single-flux-quantum (SFQ) time-to-digital converters (TDCs) for TOF-MS. • SFQ TDC can measure time intervals between multiple signals with high-resolution. • SFQ TDC can directly convert the time intervals into binary data. • We designed two types of SFQ TDCs to reduce the jitter. • The jitter is reduced to less than 100 ps. - Abstract: We have been developing a high-resolution superconducting time-of-flight mass spectrometry (TOF-MS) system, which utilizes a superconducting strip ion detector (SSID) and a single-flux-quantum (SFQ) time-to-digital converter (TDC). The SFQ TDC can measure time intervals between multiple input signals and directly convert them into binary data. In our previous study, 24-bit SFQ TDC with a 3 × 24-bit First-In First-Out (FIFO) buffer was designed and implemented using the AIST Nb standard process 2 (STP2), whose time resolution and dynamic range are 100 ps and 1.6 ms, respectively. In this study we reduce the jitter of the TDC by using two different approaches: one uses an on-chip clock generator with an on-chip low-pass filter for reducing the noise in the bias current, and the other uses a low-jitter external clock source at room temperature. We confirmed that the jitter is reduced to less than 100 ps in the latter approach

Reduction of the jitter of single-flux-quantum time-to-digital converters for time-of-flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Sano, K., E-mail: sano-kyosuke-cw@ynu.jp [Department Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Muramatsu, Y.; Yamanashi, Y.; Yoshikawa, N. [Department Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Zen, N.; Ohkubo, M. [Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)

2014-09-15

Highlights: • We proposed single-flux-quantum (SFQ) time-to-digital converters (TDCs) for TOF-MS. • SFQ TDC can measure time intervals between multiple signals with high-resolution. • SFQ TDC can directly convert the time intervals into binary data. • We designed two types of SFQ TDCs to reduce the jitter. • The jitter is reduced to less than 100 ps. - Abstract: We have been developing a high-resolution superconducting time-of-flight mass spectrometry (TOF-MS) system, which utilizes a superconducting strip ion detector (SSID) and a single-flux-quantum (SFQ) time-to-digital converter (TDC). The SFQ TDC can measure time intervals between multiple input signals and directly convert them into binary data. In our previous study, 24-bit SFQ TDC with a 3 × 24-bit First-In First-Out (FIFO) buffer was designed and implemented using the AIST Nb standard process 2 (STP2), whose time resolution and dynamic range are 100 ps and 1.6 ms, respectively. In this study we reduce the jitter of the TDC by using two different approaches: one uses an on-chip clock generator with an on-chip low-pass filter for reducing the noise in the bias current, and the other uses a low-jitter external clock source at room temperature. We confirmed that the jitter is reduced to less than 100 ps in the latter approach.

Current status of matrix-assisted laser desorption ionisation-time of flight mass spectrometry in the clinical microbiology laboratory.

Science.gov (United States)

Kok, Jen; Chen, Sharon C A; Dwyer, Dominic E; Iredell, Jonathan R

2013-01-01

The integration of matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) into many clinical microbiology laboratories has revolutionised routine pathogen identification. MALDI-TOF MS complements and has good potential to replace existing phenotypic identification methods. Results are available in a more clinically relevant timeframe, particularly in bacteraemic septic shock. Novel applications include strain typing and the detection of antimicrobial resistance, but these are not widely used. This review discusses the technical aspects, current applications, and limitations of MALDI-TOF MS.

High-sensitivity mass spectrometry with a tandem accelerator

International Nuclear Information System (INIS)

Henning, W.

1984-01-01

The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems

Effect of Rayleigh accelerations applied to an initially moving fluid. [in circular cylinders under low gravity associated with space flight

Science.gov (United States)

Dressler, R. F.; Robertson, S. J.; Spradley, L. W.

1982-01-01

The General Interpolant Method computer code was used to analyze two-dimensional unsteady thermal convection in circular cylinders under variable low-g conditions associated with space flight. When an acceleration vector was applied parallel to the thermal gradient, in the case of a fluid at rest, no convection resulted for the stable direction, and an instability led to Rayleigh convection for the opposite direction. However, when the acceleration had a component orthogonal to the gradient, convection resulted at any Rayleigh number. The effect on convection of both types of acceleration, applied concurrently or sequentially, was investigated, including the case when the resultant vector varied in direction with time. An analysis of experimental results shows that for space flight conditions, the Rayleigh accelerations induce significant, but not dominating, changes in the established convection even when the Rayleigh number is less than critical.

Rapid detection of undesired cosmetic ingredients by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Science.gov (United States)

Ouyang, Jie; An, Dongli; Chen, Tengteng; Lin, Zhiwei

2017-10-01

In recent years, cosmetic industry profits soared due to the widespread use of cosmetics, which resulted in illicit manufacturers and products of poor quality. Therefore, the rapid and accurate detection of the composition of cosmetics has become crucial. At present, numerous methods, such as gas chromatography and liquid chromatography-mass spectrometry, were available for the analysis of cosmetic ingredients. However, these methods present several limitations, such as failure to perform comprehensive and rapid analysis of the samples. Compared with other techniques, matrix-assisted laser desorption ionization time-of-flight mass spectrometry offered the advantages of wide detection range, fast speed and high accuracy. In this article, we briefly summarized how to select a suitable matrix and adjust the appropriate laser energy. We also discussed the rapid identification of undesired ingredients, focusing on antibiotics and hormones in cosmetics.

Parametric evaluation of laser ablation and ionization time-of-flight mass spectrometry with ion guide cooling cell

International Nuclear Information System (INIS)

Peng Ding; He Jian; Yu Quan; Chen Lizhi; Hang Wei; Huang Benli

2008-01-01

A novel laser ablation and ionization time-of-flight mass spectrometer has been used for direct elemental analysis of alloys. The system was incorporated with an ion guide cooling cell to reduce the kinetic energy distribution for the purpose of better resolution. Parametric studies have been conducted on the system with respect to the buffer gas pressure and the distance from sample to the nozzle to obtain the maximal signal intensities. In order to obtain satisfactory relative sensitivity coefficients (RSC) for different elements, the influence of the laser irradiance, nozzle voltage, rf frequency and voltage of the hexapole were also investigated. Under the optimized conditions, the RSC of different elements were available for direct semi-quantitative analysis. The mass resolving power (FWHM) of the spectrometer was approximately 7000 (m/Δm) and the limit of detection (LOD) was 10 -6 g/g

Hot filament-dissociation of (CH3)3SiH and (CH3)4Si, probed by vacuum ultra violet laser time of flight mass spectroscopy.

Science.gov (United States)

Sharma, Ramesh C; Koshi, Mitsuo

2006-11-01

The decomposition of trimethylsilane and tetramethylsilane has been investigated for the first time, using hot wire (catalytic) at various temperatures. Trimethylsilane is catalytic-dissociated in these species SiH(2), CH(3)SiH, CH(3), CH(2)Si. Time of flight mass spectroscopy signal of these species are linearly increasing with increasing catalytic-temperature. Time of flight mass spectroscopy (TOFMS) signals of (CH(3))(3)SiH and photodissociated into (CH(3))(2)SiH are decreasing with increasing hot filament temperature. TOFMS signal of (CH(3))(4)Si is decreasing with increasing hot wire temperature, but (CH(3))(3)Si signal is almost constant with increasing the temperature. We calculated activation energies of dissociated species of the parental molecules for fundamental information of reaction kinetics for the first time. Catalytic-dissociation of trimethylsilane, and tetramethylsilane single source time of flight coupled single photon VUV (118 nm) photoionization collisionless radicals at temperature range of tungsten filament 800-2360 K. The study is focused to understand the fundamental information on reaction kinetics of these molecules at hot wire temperature, and processes of catalytic-chemical vapour deposition (Cat-CVD) technique which could be implemented in amorphous and crystalline SiC semiconductors thin films.

Assessment of benzophenone-4 reactivity with free chlorine by liquid chromatography quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Negreira, N; Rodríguez, I; Rodil, R; Cela, R

2012-09-19

The stability of the UV filter benzophenone-4 (BP-4) in free chlorine-containing water was investigated, for the first time, by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS). High mass accuracy and resolution capabilities of this hybrid mass spectrometer were used for the reliable assignation of empirical formulae and chemical structures of BP-4 derivatives. Time-course profiles of the parent compound and its by-products were simultaneously recorded by direct injection of sample aliquots, after quenching the excess of chlorine, in the LC-QqTOF-MS system. At neutral pHs, in excess of chlorine, BP-4 showed a limited stability fitting a pseudo-first-order degradation kinetics. A noticeable reduction in the half-lives of BP-4 was observed when increasing the sample pH between 6 and 8 units and also in presence of bromide traces. The reaction pathway of this UV filter involved a first electrophilic substitution of hydrogen per chlorine (or bromide) in the phenolic ring, followed by oxidation of the carbonyl moiety to an ester group, which induced a further electrophilic substitution in the same aromatic ring. Above reactions were also noticed when mixing a BP-4 containing personal care product with chlorinated tap water and in chlorinated swimming pool and sewage water, previously spiked with a BP-4 standard. Copyright © 2012 Elsevier B.V. All rights reserved.

The performance and the characterization of laser ablation aerosol particle time-of-flight mass spectrometry (LAAP-ToF-MS)

Science.gov (United States)

Gemayel, Rachel; Hellebust, Stig; Temime-Roussel, Brice; Hayeck, Nathalie; Van Elteren, Johannes T.; Wortham, Henri; Gligorovski, Sasho

2016-05-01

Hyphenated laser ablation-mass spectrometry instruments have been recognized as useful analytical tools for the detection and chemical characterization of aerosol particles. Here we describe the performances of a laser ablation aerosol particle time-of-flight mass spectrometer (LAAP-ToF-MS) which was designed for aerodynamic particle sizing using two 405 nm scattering lasers and characterization of the chemical composition of single aerosol particle via ablation/ionization by a 193 nm excimer laser and detection in a bipolar time-of-flight mass spectrometer with a mass resolving power of m/Δm > 600.We describe a laboratory based optimization strategy for the development of an analytical methodology for characterization of atmospheric particles using the LAAP-ToF-MS instrument in combination with a particle generator, a differential mobility analyzer and an optical particle counter. We investigated the influence of particle number concentration, particle size and particle composition on the detection efficiency. The detection efficiency is a product of the scattering efficiency of the laser diodes and the ionization efficiency or hit rate of the excimer laser. The scattering efficiency was found to vary between 0.6 and 1.9 % with an average of 1.1 %; the relative standard deviation (RSD) was 17.0 %. The hit rate exhibited good repeatability with an average value of 63 % and an RSD of 18 %. In addition to laboratory tests, the LAAP-ToF-MS was used to sample ambient air during a period of 6 days at the campus of Aix-Marseille University, situated in the city center of Marseille, France. The optimized LAAP-ToF-MS methodology enables high temporal resolution measurements of the chemical composition of ambient particles, provides new insights into environmental science, and a new investigative tool for atmospheric chemistry and physics, aerosol science and health impact studies.

A compact fast data acquisition and data analysis system for time of flight mass spectrometry. Time and S.I. intensity measurements with a new multistop TDC

International Nuclear Information System (INIS)

Della-Negra, S.; Le Beyec, Y.

1987-01-01

A data acquisition and processing system for time of flight mass spectrometry, based on a PC-AT computer with an additional memory card was developed, and analysis software was written. About 100,000 counts/sec can be analyzed and stored in the memory. In the coincidence mode, 1000 start events with 10 stop events (per sec) on one time digital converter allow 10 spectra to be recorded. Examples of printouts are shown

Proton transfer reaction time-of-flight mass spectrometry advancement in detection of hazardous substances

International Nuclear Information System (INIS)

Agarwal, B.

2012-01-01

Proton Transfer Reaction Mass Spectrometry (PTR-MS) is a mass spectrometric technique based on chemical ionization, which provides very rapid measurements (within seconds) of volatile organic compounds in air, usually without special sample preparation, and with a very low detection limit. The detection and study of product ion patterns of threat agents such as explosives and drugs and some major environmental pollutants (isocyanates and polychlorinated biphenyls (PCBs)) is explored in detail here using PTR-MS, specifically Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS). The proton transfer reaction (PTR) principle works on the detection of the compound in the vapor phase. For some compounds, which have extremely low vapor pressures, both sample and inlet line heating were needed. Generally, the protonated parent molecule (MH+) is found to be the dominant product ion, which therefore provides us with a higher level of confidence in the assignment of a trace compound. However, for several compounds, dissociative proton transfer can occur at various degrees resulting in other product ions. Analysis of other compounds, such as the presence of taggants and impurities were carried out, and in certain compounds unusual E/N anomalies were discovered (E/N is an instrumental set of parameters, where E is the electric field strength and N is the number density). Head space measurements above four different drinks (plain water, tea, red wine and white wine) spiked with four different 'date rape' drugs were also conducted. (author)

Influence of Culture Media on Detection of Carbapenem Hydrolysis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

Science.gov (United States)

Ramos, Ana Carolina; Carvalhaes, Cecília Godoy; Cordeiro-Moura, Jhonatha Rodrigo; Rockstroh, Anna Carolina; Machado, Antonia Maria Oliveira; Gales, Ana Cristina

2016-07-01

In this study, we evaluated the influence of distinct bacterial growth media on detection of carbapenemase hydrolysis by matrix-assisted laser desorption ionization-time of flight mass spectrometry. False-negative results were observed for OXA-25-, OXA-26-, and OXA-72-producing Acinetobacter baumannii isolates grown on MacConkey agar medium. The other culture media showed 100% sensitivity and 100% specificity for detecting carbapenemase. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Accelerator mass spectrometry at the Rossendorf 5 MV tandem accelerator

International Nuclear Information System (INIS)

Friedrich, M.; Buerger, W.; Curian, H.; Hartmann, B.; Hentschel, E.; Matthes, H.; Probst, W.; Seidel, M.; Turuc, S.; Hebert, D.; Rothe, T.; Stolz, W.

1992-01-01

The Rossendorf electrostatic accelerators (5 MV tandem accelerator and single ended 2 MV van de Graaff accelerator) are already used for ion beam analysis. The existing methods (RBS, PIXE, ERDA, NRA, nuclear microprobe and external beam) will be completed by introduction of Accelerator Mass Spectrometry (AMS). A short description of the Rossendorf AMS system is given and first experimental results are presented. (R.P.) 4 refs.; 6 figs

Development of a Portable Single Photon Ionization-Photoelectron Ionization Time-of-Flight Mass Spectrometer

Directory of Open Access Journals (Sweden)

Yunguang Huang

2015-01-01

Full Text Available A vacuum ultraviolet lamp based single photon ionization- (SPI- photoelectron ionization (PEI portable reflecting time-of-flight mass spectrometer (TOFMS was designed for online monitoring gas samples. It has a dual mode ionization source: SPI for analyte with ionization energy (IE below 10.6 eV and PEI for IE higher than 10.6 eV. Two kinds of sampling inlets, a capillary inlet and a membrane inlet, are utilized for high concentration and trace volatile organic compounds, respectively. A mass resolution of 1100 at m/z 64 has been obtained with a total size of 40 × 31 × 29 cm, the weight is 27 kg, and the power consumption is only 70 W. A mixture of benzene, toluene, and xylene (BTX, SO2, and discharging products of SF6 were used to test its performance, and the result showed that the limit of quantitation for BTX is as low as 5 ppbv (S/N = 10 : 1 with linear dynamic ranges greater than four orders of magnitude. The portable TOFMS was also evaluated by analyzing volatile organic compounds from wine and decomposition products of SF6 inside of a gas-insulated switchgear.

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for Direct Bacterial Identification from Positive Blood Culture Pellets ▿

OpenAIRE

Prod'hom, Guy; Bizzini, Alain; Durussel, Christian; Bille, Jacques; Greub, Gilbert

2010-01-01

An ammonium chloride erythrocyte-lysing procedure was used to prepare a bacterial pellet from positive blood cultures for direct matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry analysis. Identification was obtained for 78.7% of the pellets tested. Moreover, 99% of the MALDI-TOF identifications were congruent at the species level when considering valid scores. This fast and accurate method is promising.

Quadrupole Time-of-Flight Mass Spectrometer

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: The system generates superior quality mass spectrometry (MS) and tandem mass spectrometry (MS/MS) data from both atmospheric pressure ionization (API) and...

Gas chromatography--inductively coupled plasma--time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental water samples.

Science.gov (United States)

Heisterkamp, M; Adams, F C

2001-07-01

The application of inductively coupled plasma--time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental waters is described. Construction of the transfer line was achieved by means of a relatively simple and rapid coupling procedure. Derivatization of the ionic lead species was achieved by in-situ propylation with sodium tetrapropylborate; simultaneous extraction of the derivatized compounds in hexane was followed by separation and detection by capillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight mass spectrometry. Detection limits for the different organolead species ranged from 10 to 15 fg (as Pb), corresponding to procedural detection limits between 50 and 75 ng L(-1), on the basis of a 50 mL snow sample, extraction with 200 microL hexane, and subsequent injection of 1 microL of the organic extract on to the column. The accuracy of the system was confirmed by additional analysis of the water samples by capillary gas chromatography coupled with microwave-induced plasma-atomic-emission spectrometry and the analysis of a standard reference material CRM 605 (road dust) with a certified content of trimethyllead.

Low-molecular weight protein profiling of genetically modified maize using fast liquid chromatography electrospray ionization and time-of-flight mass spectrometry.

Science.gov (United States)

Koc, Anna; Cañuelo, Ana; Garcia-Reyes, Juan F; Molina-Diaz, Antonio; Trojanowicz, Marek

2012-06-01

In this work, the use of liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC-TOFMS) has been evaluated for the profiling of relatively low-molecular weight protein species in both genetically modified (GM) and non-GM maize. The proposed approach consisted of a straightforward sample fractionation with different water and ethanol-based buffer solutions followed by separation and detection of the protein species using liquid chromatography with a small particle size (1.8 μm) C(18) column and electrospray-time-of-flight mass spectrometry detection in the positive ionization mode. The fractionation of maize reference material containing different content of transgenic material (from 0 to 5% GM) led to five different fractions (albumins, globulins, zeins, zein-like glutelins, and glutelins), all of them containing different protein species (from 2 to 52 different species in each fraction). Some relevant differences in the quantity and types of protein species were observed in the different fractions of the reference material (with different GM contents) tested, thus revealing the potential use of the proposed approach for fast protein profiling and to detect tentative GMO markers in maize. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Profiling analysis of low molecular weight heparins by multiple heart-cutting two dimensional chromatography with quadruple time-of-flight mass spectrometry.

Science.gov (United States)

Ouyang, Yilan; Zeng, Yangyang; Rong, Yinxiu; Song, Yue; Shi, Lv; Chen, Bo; Yang, Xinlei; Xu, Naiyu; Linhardt, Robert J; Zhang, Zhenqing

2015-09-01

Low molecular weight heparins (LMWHs) are polydisperse and microheterogenous mixtures of polysaccharides used as anticoagulant drugs. Profiling analysis is important for obtaining deeper insights into the structure of LMWHs. Previous oligosaccharide mapping methods are relatively low resolution and are unable to show an entire picture of the structural complexity of LMWHs. In the current study a profiling method was developed relying on multiple heart-cutting, two-dimensional, ultrahigh performance liquid chromatography with quadruple time-of-flight mass spectrometry. This represents an efficient, automated, and robust approach for profiling LMWHs. Using size-exclusion chromatography and ion-pairing reversed-phase chromatography in a two-dimensional separation, LMW components of different sizes and LMW components of the same size but with different charges and polarities can be resolved, providing a more complete picture of a LMWH. Structural information on each component was then obtained with quadrupole time-of-flight mass spectrometry. More than 80 and 120 oligosaccharides were observed and unambiguously assigned from the LMWHs, nadroparin and enoxaparin, respectively. This method might be useful for quality control of LMWHs and as a powerful tool for heparin-related glycomics.

Gas-phase pesticide measurement using iodide ionization time-of-flight mass spectrometry

Directory of Open Access Journals (Sweden)

T. Murschell

2017-06-01

Full Text Available Volatilization and subsequent processing in the atmosphere are an important environmental pathway for the transport and chemical fate of pesticides. However, these processes remain a particularly poorly understood component of pesticide lifecycles due to analytical challenges in measuring pesticides in the atmosphere. Most pesticide measurements require long (hours to days sampling times coupled with offline analysis, inhibiting observation of meteorologically driven events or investigation of rapid oxidation chemistry. Here, we present chemical ionization time-of-flight mass spectrometry with iodide reagent ions as a fast and sensitive measurement of four current-use pesticides. These semi-volatile pesticides were calibrated with injections of solutions onto a filter and subsequently volatilized to generate gas-phase analytes. Trifluralin and atrazine are detected as iodide–molecule adducts, while permethrin and metolachlor are detected as adducts between iodide and fragments of the parent analyte molecule. Limits of detection (1 s are 0.37, 0.67, 0.56, and 1.1 µg m−3 for gas-phase trifluralin, metolachlor, atrazine, and permethrin, respectively. The sensitivities of trifluralin and metolachlor depend on relative humidity, changing as much as 70 and 59, respectively, as relative humidity of the sample air varies from 0 to 80 %. This measurement approach is thus appropriate for laboratory experiments and potentially near-source field measurements.

Energy measurement using a resonator based time-of-flight system

International Nuclear Information System (INIS)

Pardo, R.C.; Clifft, B.; Johnson, K.W.; Lewis, R.N.

1983-01-01

A resonant pick-up time-of-flight system has been developed for the precise measurement of beam energy at the Argonne Tandem-Linac Accelerator System (ATLAS). The excellent timing characteristics available with ATLAS beams make it desirable to design the beam transport system to be isochronous. The advantages of the resonant time-of-flight system over other energy analysis systems such as the dispersive magnet system are numerous. The system is non-interceptive and non-destructive and preserves the beam phase space. It is non-dispersive. Path length variations are not introduced into the beam which would reduce the timing resolution. It has a large signal-to-noise ratio when compared to non-resonant beam pick-up techniques. It provides the means to precisely set the linac energy and potentially to control the energy in a feedback loop. Finally, the resonant pick-up time-of-flight system is less expensive than an equivalent magnetic system. It consists of two beam-excited resonators, associated electronics to decode the information, a computer interface to the linac PDP 11/34 control computer, and software to analyze the information and deduce the measured beam energy. This report describes the system and its components and gives a schematic overview

In-line monitoring of effluents from HTGR fuel particle preparation processes using a time-of-flight mass spectrometer

International Nuclear Information System (INIS)

Lee, D.A.; Costanzo, D.A.; Stinton, D.P.; Carpenter, J.A.; Rainey, W.T. Jr.; Canada, D.C.; Carter, J.A.

1976-08-01

The carbonization, conversion, and coating processes in the manufacture of HTGR fuel particles have been studied with the use of a time-of-flight mass spectrometer. Non-condensable effluents from these fluidized-bed processes have been monitored continuously from the beginning to the end of the process. The processes which have been monitored are these: uranium-loaded ion exchange resin carbonization, the carbothermic reduction of UO 2 to UC 2 , buffer and low temperature isotropic pyrocarbon coatings of fuel kernels, SiC coating of the kernels, and high-temperature particle annealing. Changes in concentrations of significant molecules with time and temperature have been useful in the interpretation of reaction mechanisms and optimization of process procedures

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry: a Fundamental Shift in the Routine Practice of Clinical Microbiology

Science.gov (United States)

Clark, Andrew E.; Kaleta, Erin J.; Arora, Amit

2013-01-01

SUMMARY Within the past decade, clinical microbiology laboratories experienced revolutionary changes in the way in which microorganisms are identified, moving away from slow, traditional microbial identification algorithms toward rapid molecular methods and mass spectrometry (MS). Historically, MS was clinically utilized as a high-complexity method adapted for protein-centered analysis of samples in chemistry and hematology laboratories. Today, matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) MS is adapted for use in microbiology laboratories, where it serves as a paradigm-shifting, rapid, and robust method for accurate microbial identification. Multiple instrument platforms, marketed by well-established manufacturers, are beginning to displace automated phenotypic identification instruments and in some cases genetic sequence-based identification practices. This review summarizes the current position of MALDI-TOF MS in clinical research and in diagnostic clinical microbiology laboratories and serves as a primer to examine the “nuts and bolts” of MALDI-TOF MS, highlighting research associated with sample preparation, spectral analysis, and accuracy. Currently available MALDI-TOF MS hardware and software platforms that support the use of MALDI-TOF with direct and precultured specimens and integration of the technology into the laboratory workflow are also discussed. Finally, this review closes with a prospective view of the future of MALDI-TOF MS in the clinical microbiology laboratory to accelerate diagnosis and microbial identification to improve patient care. PMID:23824373

Matrix-assisted laser desorption ionization-time of flight mass spectrometry: a fundamental shift in the routine practice of clinical microbiology.

Science.gov (United States)

Clark, Andrew E; Kaleta, Erin J; Arora, Amit; Wolk, Donna M

2013-07-01

Within the past decade, clinical microbiology laboratories experienced revolutionary changes in the way in which microorganisms are identified, moving away from slow, traditional microbial identification algorithms toward rapid molecular methods and mass spectrometry (MS). Historically, MS was clinically utilized as a high-complexity method adapted for protein-centered analysis of samples in chemistry and hematology laboratories. Today, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) MS is adapted for use in microbiology laboratories, where it serves as a paradigm-shifting, rapid, and robust method for accurate microbial identification. Multiple instrument platforms, marketed by well-established manufacturers, are beginning to displace automated phenotypic identification instruments and in some cases genetic sequence-based identification practices. This review summarizes the current position of MALDI-TOF MS in clinical research and in diagnostic clinical microbiology laboratories and serves as a primer to examine the "nuts and bolts" of MALDI-TOF MS, highlighting research associated with sample preparation, spectral analysis, and accuracy. Currently available MALDI-TOF MS hardware and software platforms that support the use of MALDI-TOF with direct and precultured specimens and integration of the technology into the laboratory workflow are also discussed. Finally, this review closes with a prospective view of the future of MALDI-TOF MS in the clinical microbiology laboratory to accelerate diagnosis and microbial identification to improve patient care.

Design of a ram accelerator mass launch system

Science.gov (United States)

Aarnio, Michael; Armerding, Calvin; Berschauer, Andrew; Christofferson, Erik; Clement, Paul; Gohd, Robin; Neely, Bret; Reed, David; Rodriguez, Carlos; Swanstrom, Fredrick

1988-01-01

The ram accelerator mass launch system has been proposed to greatly reduce the costs of placing acceleration-insensitive payloads into low earth orbit. The ram accelerator is a chemically propelled, impulsive mass launch system capable of efficiently accelerating relatively large masses from velocities of 0.7 km/sec to 10 km/sec. The principles of propulsion are based on those of a conventional supersonic air-breathing ramjet; however the device operates in a somewhat different manner. The payload carrying vehicle resembles the center-body of the ramjet and accelerates through a stationary tube which acts as the outer cowling. The tube is filled with premixed gaseous fuel and oxidizer mixtures that burn in the vicinity of the vehicle's base, producing a thrust which accelerates the vehicle through the tube. This study examines the requirement for placing a 2000 kg vehicle into a 500 km circular orbit with a minimum amount of on-board rocket propellant for orbital maneuvers. The goal is to achieve a 50 pct payload mass fraction. The proposed design requirements have several self-imposed constraints that define the vehicle and tube configurations. Structural considerations on the vehicle and tube wall dictate an upper acceleration limit of 1000 g's and a tube inside diameter of 1.0 m. In-tube propulsive requirements and vehicle structural constraints result in a vehicle diameter of 0.76 m, a total length of 7.5 m and a nose-cone half angle of 7 degrees. An ablating nose-cone constructed from carbon-carbon composite serves as the thermal protection mechanism for atmospheric transit.

Quantification of VX Nerve Agent in Various Food Matrices by Solid-Phase Extraction Ultra-Performance Liquid ChromatographyTime-of-Flight Mass Spectrometry

Science.gov (United States)

2016-04-01

QUANTIFICATION OF VX NERVE AGENT IN VARIOUS FOOD MATRICES BY SOLID - PHASE EXTRACTION ULTRA-PERFORMANCE...TITLE AND SUBTITLE Quantification of VX Nerve Agent in Various Food Matrices by Solid - Phase Extraction Ultra-Performance Liquid Chromatography...QUANTIFICATION OF VX NERVE AGENT IN VARIOUS FOOD MATRICES BY SOLID - PHASE EXTRACTION ULTRA-PERFORMANCE LIQUID CHROMATOGRAPHY–TIME-OF-FLIGHT MASS

A new beam profile monitor and time of flight system for CologneAMS

Energy Technology Data Exchange (ETDEWEB)

Pascovici, G. [CologneAMS, University of Cologne (Germany); Dewald, A., E-mail: dewald@ikp.uni-koeln.de [CologneAMS, University of Cologne (Germany); Institute of Nuclear Physics, University of Cologne (Germany); Heinze, S., E-mail: heinze@ikp.uni-koeln.de [CologneAMS, University of Cologne (Germany); Fink, L.; Mueller-Gatermann, C.; Schiffer, M.; Feuerstein, C. [CologneAMS, University of Cologne (Germany); Pfeiffer, M.; Jolie, J.; Thiel, S.; Zell, K.O.; Arnopolina, O. [Institute of Nuclear Physics, University of Cologne (Germany); Blanckenburg, F. von [GFZ, German Research Centre for Geosciences, Potsdam (Germany)

2013-01-15

A complex beam detector consisting of a high-resolution beam profile monitor (BPM) and a time of flight (TOF) spectrometer with tracking capabilities was designed especially for the special needs of the Cologne center for accelerator mass spectrometry (CologneAMS). The beam detector assembly is designed to match the beam specifications of the 6 MV Tandetron AMS setup and its data acquisition system. It will have a reconfigurable structure, either as a fast TOF subsystem with a ca. 10 cm{sup 2} equivalent active area, or as a more complex BPM-TOF detector with beam tracking capabilities and a larger active area (16 cm{sup 2}). The purpose of this detector is to suppress background during spectrometry of heavy ions (U, Cm, Pu, Am etc.) and to suppress isobaric interferences such as {sup 36}S in {sup 36}Cl spectra.

Profiling the indole alkaloids in yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Sun, Jianghao; Baker, Andrew; Chen, Pei

2011-09-30

An ultra-performance liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry (UPLC/IM-QTOF-MS) method was developed for profiling the indole alkaloids in yohimbe bark. Many indole alkaloids with the yohimbine or ajmalicine core structure, plus methylated, oxidized and reduced species, were characterized. Common fragments and mass differences are described. It was shown that the use of IMS could provide another molecular descriptor, i.e. molecular shape by rotationally averaged collision cross-section; this is of great value for identification of constituents when reference materials are usually not available. Using the combination of high resolution (~40000) accurate mass measurement with time-aligned parallel (TAP) fragmentation, MS(E) (where E represents collision energy), ion mobility mass spectrometry (IMS) and UPLC chromatography, a total 55 indole alkaloids were characterized and a few new indole alkaloids are reported for the first time. Published in 2011 by John Wiley & Sons, Ltd.

Fast neutron measurements at the nELBE time-of-flight facility

Directory of Open Access Journals (Sweden)

Junghansa A. R.

2015-01-01

Full Text Available The compact neutron-time-of-flight facility nELBE at the superconducting electron accelerator ELBE of Helmholtz-Zentrum Dresden-Rossendorf has been rebuilt. A new enlarged experimental hall with a flight path of up to 10 m is available for neutron time-of-flight experiments in the fast energy range from about 50 keV to 10 MeV. nELBE is intended to deliver nuclear data of fast neutron nuclear interactions e.g. for the transmutation of nuclear waste and improvement of neutron physical simulations of innovative nuclear systems. The experimental programme consists of transmission measurements of neutron total cross sections, elastic and inelastic scattering cross section measurements, and neutron induced fission cross sections. The inelastic scattering to the first few excited states in 56Fe was investigated by measuring the gamma production cross section with an HPGe detector. The neutron induced fission of 242Pu was studied using fast ionisation chambers with large homogeneous actinide deposits.

Use of matrix-assisted laser desorption ionization-time of flight mass spectrometry for caspofungin susceptibility testing of Candida and Aspergillus species.

Science.gov (United States)

De Carolis, Elena; Vella, Antonietta; Florio, Ada R; Posteraro, Patrizia; Perlin, David S; Sanguinetti, Maurizio; Posteraro, Brunella

2012-07-01

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) was evaluated for testing susceptibility to caspofungin of wild-type and fks mutant isolates of Candida and Aspergillus. Complete essential agreement was observed with the CLSI reference method, with categorical agreement for 94.1% of the Candida isolates tested. Thus, MALDI-TOF MS is a reliable and accurate method to detect fungal isolates with reduced caspofungin susceptibility.

Particle identification by time-of-flight measurement in the SAPHIR

International Nuclear Information System (INIS)

Hoffmann-Rothe, P.

1993-02-01

Using photoproduction data which have been measured with the SAPHIR-detector with different target materials (C H 2 solid , H 2 liquid , D 2 liquid ) a detailed investigation and discussion of the detectors performance to measure the time of flight of charged particles and to separate between particles of different mass has been accomplished. A FORTRAN program has been written which provides a calibration of the scintillator panels of the TOF hodoscopes, calculates correction factors for the time-walk effect an finally, by combining the time of flight with track momentum measurement, determines particle masses. The current configuration of the detector makes it possible to separate between proton and pion up to a particle momentum of 1.6 GeV/c. Proton and kaon can be separated up to a momentum of 1.3 GeV/c, kaon and pion up to a momentum of 0.85 GeV/c. (prog.) [de

Screening of environmental contaminants in honey bee wax comb using gas chromatography-high-resolution time-of-flight mass spectrometry.

Science.gov (United States)

Gómez-Ramos, M M; García-Valcárcel, A I; Tadeo, J L; Fernández-Alba, A R; Hernando, M D

2016-03-01

This study reports an analytical approach intended to be used for investigation of non-targeted environmental contaminants and to characterize the organic pollution pattern of bee wax comb samples. The method comprises a generic extraction followed by detection with gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-TOF-MS), operated in electron impact ionization (EI) mode. The screening approach for the investigation of non-targeted contaminants consisted of initial peak detection by deconvolution and matching the first-stage mass spectra EI-MS(1) with a nominal mass spectral library. To gain further confidence in the structural characterization of the contaminants under investigation, the molecular formula of representative ions (molecular ion when present in the EI spectrum) and, for at least other two fragment ions, was provided for those with an accurate mass scoring (mass error contaminants in 50 samples of bee wax comb. This approach has allowed the tentative identification of some GC-amenable contaminants belonging to different chemical groups, among them, phthalates and polycyclic aromatic hydrocarbons (PAHs), along with residues of veterinary treatments used in apiculture.

Differentiation of Clinically Relevant mucorales Rhizopus microsporus and R. arrhizus by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS)

NARCIS (Netherlands)

Dolatabadi, S.; Kolecka, A.; Versteeg, Matthijs; de Hoog, Sybren G; Boekhout, Teun

This study addresses the usefulness of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) for reliable identification of the two most frequently occuring clinical species of Rhizopus, namely R. arrhizus with its two varieties arrhizus and delemar and R.

Rayleigh-Taylor mixing with time-dependent acceleration

Science.gov (United States)

Abarzhi, Snezhana

2016-10-01

We extend the momentum model to describe Rayleigh-Taylor (RT) mixing driven by a time-dependent acceleration. The acceleration is a power-law function of time, similarly to astrophysical and plasma fusion applications. In RT flow the dynamics of a fluid parcel is driven by a balance per unit mass of the rates of momentum gain and loss. We find analytical solutions in the cases of balanced and imbalanced gains and losses, and identify their dependence on the acceleration exponent. The existence is shown of two typical regimes of self-similar RT mixing-acceleration-driven Rayleigh-Taylor-type and dissipation-driven Richtymer-Meshkov-type with the latter being in general non-universal. Possible scenarios are proposed for transitions from the balanced dynamics to the imbalanced self-similar dynamics. Scaling and correlations properties of RT mixing are studied on the basis of dimensional analysis. Departures are outlined of RT dynamics with time-dependent acceleration from canonical cases of homogeneous turbulence as well as blast waves with first and second kind self-similarity. The work is supported by the US National Science Foundation.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry identification of large colony beta-hemolytic streptococci containing Lancefield groups A, C, and G

DEFF Research Database (Denmark)

Salgård Jensen, Christian; Dam-Nielsen, Casper; Arpi, Magnus

2015-01-01

BACKGROUND: The aim of this study was to investigate whether large colony beta-hemolytic streptococci containing Lancefield groups A, C, and G can be adequately identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-ToF). Previous studies show varying...

Ion-neutral potential models in atmospheric pressure ion mobility time-of-flight mass spectrometry IM(tof)MS.

Science.gov (United States)

Steiner, Wes E; English, William A; Hill, Herbert H

2006-02-09

The ion mobilities and their respective masses of several classes of amines (primary, secondary, and tertiary) were measured by electrospray ionization atmospheric pressure ion mobility time-of-flight mass spectrometry IM(tof)MS. The experimental data obtained were comparatively analyzed by the one-temperature kinetic theory of Chapman-Enskog. Several theoretical models were used to estimate the collision cross-sections; they include the rigid-sphere, polarization-limit, 12-6-4, and 12-4 potential models. These models were investigated to represent the interaction potentials contained within the collision integral that occurs between the polyatomic ions and the neutral drift gas molecules. The effectiveness of these collision cross-section models on predicting the mobility of these amine ions was explored. Moreover, the effects of drift gas selectivity on the reduced-mass term and in the collision cross-section term was examined. Use of a series of drift gases, namely, helium, neon, argon, nitrogen, and carbon dioxide, made it possible to distinguish between mass effects and polarizability effects. It was found that the modified 12-4 potential that compensates for the center of charge not being at the same location as the centers of mass showed improved agreement over the other collision cross-section models with respect to experimental data.

Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Caspofungin Susceptibility Testing of Candida and Aspergillus Species

Science.gov (United States)

De Carolis, Elena; Vella, Antonietta; Florio, Ada R.; Posteraro, Patrizia; Perlin, David S.; Posteraro, Brunella

2012-01-01

Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) was evaluated for testing susceptibility to caspofungin of wild-type and fks mutant isolates of Candida and Aspergillus. Complete essential agreement was observed with the CLSI reference method, with categorical agreement for 94.1% of the Candida isolates tested. Thus, MALDI-TOF MS is a reliable and accurate method to detect fungal isolates with reduced caspofungin susceptibility. PMID:22535984

Discrimination of Bacillus anthracis Spores by Direct in-situ Analysis of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

International Nuclear Information System (INIS)

Jeong, Youngsu; Lee, Jonghee; Kim, Seongsoo

2013-01-01

The rapid and accurate identification of biological agents is a critical step in the case of bio-terror and biological warfare attacks. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been widely used for the identification of microorganisms. In this study, we describe a method for the rapid and accurate discrimination of Bacillus anthracis spores using MALDI-TOF MS. Our direct in-situ analysis of MALDI-TOF MS does not involve subsequent high-resolution mass analyses and sample preparation steps. This method allowed the detection of species-specific biomarkers from each Bacillus spores. Especially, B. anthracis spores had specific biomarker peaks at 2503, 3089, 3376, 6684, 6698, 6753, and 6840 m/z. Cluster and PCA analyses of the mass spectra of Bacillus spores revealed distinctively separated clusters and within-groups similarity. Therefore, we believe that this method is effective in the real-time identification of biological warfare agents such as B. anthracis as well as other microorganisms in the field

Discrimination of Bacillus anthracis Spores by Direct in-situ Analysis of Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Jeong, Youngsu; Lee, Jonghee; Kim, Seongsoo [Agency for Defense Development, Daejeon (Korea, Republic of)

2013-09-15

The rapid and accurate identification of biological agents is a critical step in the case of bio-terror and biological warfare attacks. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has been widely used for the identification of microorganisms. In this study, we describe a method for the rapid and accurate discrimination of Bacillus anthracis spores using MALDI-TOF MS. Our direct in-situ analysis of MALDI-TOF MS does not involve subsequent high-resolution mass analyses and sample preparation steps. This method allowed the detection of species-specific biomarkers from each Bacillus spores. Especially, B. anthracis spores had specific biomarker peaks at 2503, 3089, 3376, 6684, 6698, 6753, and 6840 m/z. Cluster and PCA analyses of the mass spectra of Bacillus spores revealed distinctively separated clusters and within-groups similarity. Therefore, we believe that this method is effective in the real-time identification of biological warfare agents such as B. anthracis as well as other microorganisms in the field.

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for identification of clinically important yeast species.

Science.gov (United States)

Stevenson, Lindsay G; Drake, Steven K; Shea, Yvonne R; Zelazny, Adrian M; Murray, Patrick R

2010-10-01

We evaluated the use of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the rapid identification of yeast species. Using Bruker Daltonics MALDI BioTyper software, we created a spectral database library with m/z ratios of 2,000 to 20,000 Da for 109 type and reference strains of yeast (44 species in 8 genera). The database was tested for accuracy by use of 194 clinical isolates (23 species in 6 genera). A total of 192 (99.0%) of the clinical isolates were identified accurately by MALDI-TOF MS. The MALDI-TOF MS-based method was found to be reproducible and accurate, with low consumable costs and minimal preparation time.

Collisional activation by MALDI tandem time-of-flight mass spectrometry induces intramolecular migration of amide hydrogens in protonated peptides

DEFF Research Database (Denmark)

Jørgensen, Thomas J D; Bache, Nicolai; Roepstorff, Peter

2005-01-01

of doubly protonated peptides that the original regioselective deuterium pattern of these peptides is completely erased (Jørgensen, T. J. D., Gårdsvoll, H., Ploug, M., and Roepstorff, P. (2005) Intramolecular migration of amide hydrogens in protonated peptides upon collisional activation. J. Am. Chem. Soc...... randomization among all exchangeable sites (i.e. all N- and O-linked hydrogens) also occurs upon high energy collisional activation of singly protonated peptides. This intense proton/deuteron traffic precludes the use of MALDI tandem time-of-flight mass spectrometry to obtain reliable information...

Laser desorption/ionization time-of-flight mass spectrometry of triacylglycerols and other components in fingermark samples.

Science.gov (United States)

Emerson, Beth; Gidden, Jennifer; Lay, Jackson O; Durham, Bill

2011-03-01

The chemical composition of fingermarks could potentially be important for determining investigative leads, placing individuals at the time of a crime, and has applications as biomarkers of disease. Fingermark samples containing triacylglycerols (TAGs) and other components were analyzed using laser desorption/ionization (LDI) time-of-flight mass spectrometry (TOF MS). Only LDI appeared to be useful for this application while conventional matrix-assisted LDI-TOF MS was not. Tandem MS was used to identify/confirm selected TAGs. A limited gender comparison, based on a simple t-distribution and peaks intensities, indicated that two TAGs showed gender specificity at the 95% confidence level and two others at 97.5% confidence. Because gender-related TAGs differences were most often close to the standard deviation of the measurements, the majority of the TAGs showed no gender specificity. Thus, LDI-TOF MS is not a reliable indicator of gender based on fingermark analysis. Cosmetic ingredients present in some samples were identified. © 2011 American Academy of Forensic Sciences.

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry in the identification of organic compounds in atmospheric aerosols from coniferous forest

NARCIS (Netherlands)

Kallio, M.; Jussila, M.; Rissanen, T.; Anttila, P.; Hartonen, K.; Reissell, A.; Vreuls, R.J.J.; Adahchour, M.; Hyotylainen, T.

2006-01-01

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF-MS) was applied in the identification of organic compounds in atmospheric aerosols from coniferous forest. The samples were collected at Hyytiälä, Finland, as part of the QUEST campaign, in

Characterization of foot- and mouth disease virus antigen by surface-enhanced laser desorption ionization-time of flight-mass spectrometry in aqueous and oil-emulsion formulations

NARCIS (Netherlands)

Harmsen, M.M.; Jansen, J.; Westra, D.F.; Coco-Martin, J.M.

2010-01-01

We have used a novel method, surface-enhanced laser desorption ionization-time of flight-mass spectrometry (SELDI-TOF-MS), to characterize foot-and-mouth disease virus (FMDV) vaccine antigens. Using specific capture with FMDV binding recombinant antibody fragments and tryptic digestion of FMDV

Construction and simulation of a multi-reflection time-of-flight mass spectrometer at the University of Notre Dame

Energy Technology Data Exchange (ETDEWEB)

Schultz, B.E., E-mail: bschult4@nd.edu; Kelly, J.M.; Nicoloff, C.; Long, J.; Ryan, S.; Brodeur, M.

2016-06-01

One of the most significant problems in the production of rare isotopes is the simultaneous production of contaminants, often time isobaric. Thus, a high-resolution beam purification method is required which needs to be compatible with both the low yield and short half-life of the desired radionuclide. A multi-reflection time-of-flight mass spectrometer meets all these criteria, in addition to boasting a smaller footprint relative to traditional separator dipole magnets. Such a device is currently under construction at the University of Notre Dame and is intended to be coupled to the IG-ISOL source of the planned cyclotron facility. The motivation and conceptual design are presented, as well as the status of simulations to determine the feasibility of using a Bradbury–Nielsen gate for bunching ion beams during initial system testing.

Characterization of a Carbon Nanotube Field Emission Electron Gun for the VAPoR Miniaturized Pyrolysis-Time-of-Flight Mass Spectrometer

Science.gov (United States)

Getty, Stephanie; Li, Mary; Costen, Nicholas; Hess, Larry; Feng, Steve; King, Todd; Brinckerhoff, William; Mahaffy, Paul; Glavin, Daniel

2009-01-01

We are developing the VAPoR (Volatile Analysis by Pyrolysis of Regolith) instrument towards studying soil composition, volatiles, and trapped noble gases in the polar regions of the Moon. VAPOR will ingest a soil sample and conduct analysis by pyrolysis and time-of-flight mass spectrometry (ToF-MS). Here, we describe miniaturization efforts within this development, including a carbon nanotube (CNT) field emission electron gun that is under consideration for use as the electron impact ionization source for the ToF-MS.

Accelerator mass spectrometry: state of the art

Energy Technology Data Exchange (ETDEWEB)

Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.

Accelerator mass spectrometry: state of the art

Energy Technology Data Exchange (ETDEWEB)

Tuniz, C [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Accelerator Mass Spectrometry (AMS) is the analytical technique of choice for the detection of long-lived radionuclides which cannot be practically analysed with decay counting or conventional mass spectrometry. The main use of AMS has been in the analysis of radiocarbon and other cosmogenic radionuclides for archaeological, geological and environmental applications. In addition, AMS has been recently applied in biomedicine to study exposure of human tissues to chemicals and biomolecules at attomole levels. There is also a world-wide effort to analyse rare nuclides of heavier masses, such as long-lived actinides, with important applications in safeguards and nuclear waste disposal. The use of AMS is limited by the expensive accelerator technology required and there are several attempts to develop smaller and cheaper AMS spectrometers. 5 refs.

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.

An ion source for radiofrequency-pulsed glow discharge time-of-flight mass spectrometry

International Nuclear Information System (INIS)

González Gago, C.; Lobo, L.; Pisonero, J.; Bordel, N.; Pereiro, R.; Sanz-Medel, A.

2012-01-01

A Grimm-type glow discharge (GD) has been designed and constructed as an ion source for pulsed radiofrequency GD spectrometry when coupled to an orthogonal time of flight mass spectrometer. Pulse shapes of argon species and analytes were studied as a function of the discharge conditions using a new in-house ion source (UNIOVI GD) and results have been compared with a previous design (PROTOTYPE GD). Different behavior and shapes of the pulse profiles have been observed for the two sources evaluated, particularly for the plasma gas ionic species detected. In the more analytically relevant region (afterglow), signals for 40 Ar + with this new design were negligible, while maximum intensity was reached earlier in time for 41 (ArH) + than when using the PROTOTYPE GD. Moreover, while maximum 40 Ar + signals measured along the pulse period were similar in both sources, 41 (ArH) + and 80 (Ar 2 ) + signals tend to be noticeable higher using the PROTOTYPE chamber. The UNIOVI GD design was shown to be adequate for sensitive direct analysis of solid samples, offering linear calibration graphs and good crater shapes. Limits of detection (LODs) are in the same order of magnitude for both sources, although the UNIOVI source provides slightly better LODs for those analytes with masses slightly higher than 41 (ArH) + . - Highlights: ► A new RF-pulsed GD ion source (UNIOVI GD) coupled to TOFMS has been characterized. ► Linear calibration graphs and LODs in the low ppm range are achieved. ► Craters with flat bottoms and vertical walls are obtained. ► UNIOVI source can be easily cleaned as it does not require flow tube. ► UNIOVI GD has a simple design and thus its manufacture is easy and cheap.

Structural elucidation and identification of a new derivative of phenethylamine using quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Sekuła, Karolina; Zuba, Dariusz

2013-09-30

In recent years, the phenomenon of uncontrolled distribution of new psychoactive substances that were marketed without prior toxicological studies has been observed. Because many designer drugs are related in chemical structure, the potential for misidentifying them is an important problem. It is therefore essential to develop an analytical procedure for unequivocal elucidation of the structures of these compounds. The issue has been discussed in the context of 25I-NBMD [2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2,3-methylenedioxyphenyl)methyl]ethanamine], a psychoactive substance first discovered on the drug market in 2012. The substance was extracted from blotter papers with methanol. Separation was achieved via liquid chromatography. Analysis was conducted by electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOFMS). Identification of the psychoactive component was supported by electron impact gas chromatography/mass spectrometry (GC/EI-MS). The high accuracy of the LC/ESI-QTOFMS method allowed the molecular mass of the investigated substance (M(exp) = 441.0438 Da; mass error, ∆m = 0.2 ppm) and the formulae of ions formed during fragmentation to be determined. The main ions were recorded at m/z = 135.0440, 290.9876 and 305.9981. Structures of the obtained ions were elucidated in the tandem mass spectrometry (MS/MS) experiments by comparing them to mass spectra of previously detected derivatives of phenethylamine. The performed study indicated the potential for using LC/QTOFMS method to identify new designer drugs. This technique can be used supplementary to standard GC/MS. Prior knowledge of the fragmentation mechanisms of phenethylamines allowed to predict the mass spectra of the novel substance--25I-NBMD. Copyright © 2013 John Wiley & Sons, Ltd.

Cassini Ion Mass Spectrometer Peak Calibrations from Statistical Analysis of Flight Data

Science.gov (United States)

Woodson, A. K.; Johnson, R. E.

2017-12-01

The Cassini Ion Mass Spectrometer (IMS) is an actuating time-of-flight (TOF) instrument capable of resolving ion mass, energy, and trajectory over a field of view that captures nearly the entire sky. One of three instruments composing the Cassini Plasma Spectrometer, IMS sampled plasma throughout the Kronian magnetosphere from 2004 through 2012 when it was permanently disabled due to an electrical malfunction. Initial calibration of the flight instrument at Southwest Research Institute (SwRI) was limited to a handful of ions and energies due to time constraints, with only about 30% of planned measurements carried out prior to launch. Further calibration measurements were subsequently carried out after launch at SwRI and Goddard Space Flight Center using the instrument prototype and engineering model, respectively. However, logistical differences among the three calibration efforts raise doubts as to how accurately the post-launch calibrations describe the behavior of the flight instrument. Indeed, derived peak parameters for some ion species differ significantly from one calibration to the next. In this study we instead perform a statistical analysis on 8 years of flight data in order to extract ion peak parameters that depend only on the response of the flight instrument itself. This is accomplished by first sorting the TOF spectra based on their apparent compositional similarities (e.g. primarily water group ions, primarily hydrocarbon ions, etc.) and normalizing each spectrum. The sorted, normalized data are then binned according to TOF, energy, and counts in order to generate energy-dependent probability density maps of each ion peak contour. Finally, by using these density maps to constrain a stochastic peak fitting algorithm we extract confidence intervals for the model parameters associated with various measured ion peaks, establishing a logistics-independent calibration of the body of IMS data gathered over the course of the Cassini mission.

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry of polychlorinated biphenyls

International Nuclear Information System (INIS)

Matsui, Taiki; Uchimura, Tomohiro; Imasaka, Totaro

2011-01-01

A sample mixture of polychlorinated biphenyls (PCBs) was measured by gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) using four types of laser sources. When a fourth harmonic emission (266 nm) of a picosecond Nd:YAG laser (1064 nm) was utilized, highly chlorinated PCBs larger than hepta-CBs were not observed. A fifth harmonic emission (213 nm) of the picosecond Nd:YAG laser allowed the measurement of PCBs from di-CBs to octa-CBs, and the limit of detection (LOD) was several pg for each component of PCBs. The LOD for the total amount of PCBs, which was calculated using the protocol provided by the Ministry of the Environment, Japan, was 1000 pg. The signal intensity of the congeners with chlorine atoms at the ortho positions (non-coplanar PCBs) was enhanced by using the fifth harmonic emission. When the fourth harmonic emission remaining after fifth harmonic generation was simultaneously used, the LOD for total PCBs was improved to 667 pg. The PCB sample was also measured using a third harmonic emission (267 nm) of a femtosecond Ti:sapphire laser (800 nm), providing an LOD of 677 pg. Thus, the two-color beam (266/213 nm) of a picosecond Nd:YAG laser had a comparable, or even slightly superior, performance to the more expensive femtosecond Ti:sapphire laser.

Mass spectrometry by means of tandem accelerators

International Nuclear Information System (INIS)

Tuniz, C.

1985-01-01

Mass spectrometry based on an accelerator allows to measure rare cosmogenic isotopes found in natural samples with isotopic abundances up to 10E-15. The XTU Tandem of Legnaro National Laboratories can measure mean heavy isotopes (36Cl, 41Ca, 129I) in applications interesting cosmochronology and Medicine. The TTT-3 Tandem of the Naples University has been modified in view of precision studies of C14 in Archeology, Paleantology and Geology. In this paper a review is made of principles and methodologies and of some applicationy in the framework of the National Program for mass spectrametry research with the aid of accelerators

Atom counting with accelerator mass spectrometry

International Nuclear Information System (INIS)

Kutschera, Walter

1995-01-01

A brief review of the current status and some recent applications of accelerator mass spectrometry (AMS) are presented. Some connections to resonance ionization mass spectroscopy (RIS) as the alternate atom counting method are discussed

Accelerator mass spectrometry-current status in techniques and applications

International Nuclear Information System (INIS)

Imamura, Mineo; Nagai, Hisao; Kobayashi, Koichi.

1991-01-01

Accelerator mass spectrometry (AMS) is the mass spectrometry by incorporating an accelerator. After samples are ionized, they are accelerated to a certain energy, and mass, energy, nuclear charge (atomic number) are distinguished, and ion counting is made one by one with a heavy ion detector. For the measurement of long half-life radioisotopes, mass spectrometry has been used because of the high sensitivity, but in low energy mass spectrometry, there are the difficulties due to the mixing of the molecular ions having nearly same mass and the existence of isobars. One of the methods solving these difficulties is an accelerator which enables background-free measurement. The progress of AMS is briefly described, and at present, it is carried out in about 30 facilities in the world. In AMS, the analysis is carried out in the order of the ionization of samples, the acceleration of beam, the electron stripping with a thin film, the sorting of the momentum and energy of beam and the identification of particles. The efficiency, sensitivity and accuracy of detection and the application are reported. (K.I.)

Identification of wheat varieties using matrix-assisted laserdesorption/ionisation time-of-flight mass spectrometry and anartificial neural network

DEFF Research Database (Denmark)

Bloch, Helle Aagaard; Kesmir, Can; Petersen, Marianne Kjerstine

1999-01-01

of this novelmethod with respect to various experimental parameters has been tested. The results can be summarised: (i)With this approach 97% of the wheat varieties can be classified correctly with a corresponding correlationcoefficient of 1.0, (ii) The method is fast since the time of extracting gliadins from flour......A novel tool for variety identification of wheat (Triticum aestivum L.) has been developed: an artificialneural network (ANN) is used to classify the gliadin fraction analysed by matrix-assisted laserdesorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS). The robustness...... by the identity of the operator making theanalysis. This study demonstrates that a combination of an ANN and MALDI-TOFMS analysis of thegliadin fraction provides a fast and reliable tool for the variety identification of wheat. Copyright 1999 JohnWiley & Sons, Ltd....

Characterization of olive oil volatiles by multi-step direct thermal desorption-comprehensive gas chromatography-time-of-flight mass spectrometry using a programmed temperature vaporizing injector

NARCIS (Netherlands)

de Koning, S.; Kaal, E.; Janssen, H.-G.; van Platerink, C.; Brinkman, U.A.Th.

2008-01-01

The feasibility of a versatile system for multi-step direct thermal desorption (DTD) coupled to comprehensive gas chromatography (GC × GC) with time-of-flight mass spectrometric (TOF-MS) detection is studied. As an application the system is used for the characterization of fresh versus aged olive

Ultra-fast liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry for the rapid phenolic profiling of red maple (Acer rubrum) leaves.

Science.gov (United States)

Li, Chunting; Seeram, Navindra P

2018-03-07

The red maple (Acer rubrum) species is economically important to North America because of its sap, which is used to produce maple syrup. In addition, various other red maple plant parts, including leaves, were used as a traditional medicine by the Native Americans. Currently, red maple leaves are being used for nutraceutical and cosmetic applications but there are no published analytical methods for comprehensive phytochemical characterization of this material. Herein, a rapid and sensitive method using liquid chromatography with electrospray ionization time-of-flight tandem mass spectrometry was developed to characterize the phenolics in a methanol extract of red maple leaves and a proprietary phenolic-enriched red maple leaves extract (Maplifa™). Time-of-flight mass spectrometry and tandem mass spectrometry experiments led to the identification of 106 phenolic compounds in red maples leaves with the vast majority of these compounds also detected in Maplifa™. The compounds included 68 gallotannins, 25 flavonoids, gallic acid, quinic acid, catechin, epicatechin, and nine other gallic acid derivatives among which 11 are potentially new and 75 are being reported from red maple for the first time. The developed method to characterize red maple leaves phenolics is rapid and highly sensitive and could aid in future standardization and quality control of this botanical ingredient. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A dedicated AMS setup for medium mass isotopes at the Cologne FN tandem accelerator

Science.gov (United States)

Schiffer, M.; Altenkirch, R.; Feuerstein, C.; Müller-Gatermann, C.; Hackenberg, G.; Herb, S.; Bhandari, P.; Heinze, S.; Stolz, A.; Dewald, A.

2017-09-01

AMS measurements of medium mass isotopes, e.g. of 53Mn and 60Fe, are gaining interest in various fields of operation, especially geoscience. Therefore a dedicated AMS setup has been built at the Cologne 10 MV FN tandem accelerator. This setup is designed to obtain a sufficient suppression of the stable isobars at energies around 100 MeV. In this contribution we report on the actual status of the new setup and the first in-beam tests of its individual components. The isobar suppression is done with (dE/dx) techniques using combinations of energy degrader foils with an electrostatic analyzer (ESA) and a time of flight (ToF) system, as well as a (dE/dx),E gas ionization detector. Furthermore, the upgraded ion source and its negative ion yield measurement for MnO- are presented.

Qualitative and Quantitative Analysis of Andrographis paniculata by Rapid Resolution Liquid Chromatography/Time-of-Flight Mass Spectrometry

Directory of Open Access Journals (Sweden)

Jian-Fei Qin

2013-09-01

Full Text Available A rapid resolution liquid chromatography/time-of-flight tandem mass spectrometry (RRLC-TOF/MS method was developed for qualitative and quantitative analysis of the major chemical constituents in Andrographis paniculata. Fifteen compounds, including flavonoids and diterpenoid lactones, were unambiguously or tentatively identified in 10 min by comparing their retention times and accurate masses with standards or literature data. The characteristic fragmentation patterns of flavonoids and diterpenoid lactones were summarized, and the structures of the unknown compounds were predicted. Andrographolide, dehydroandrographolide and neoandrographolide were further quantified as marker substances. It was found that the calibration curves for all analytes showed good linearity (R2 > 0.9995 within the test ranges. The overall limits of detection (LODs and limits of quantification (LOQs were 0.02 μg/mL to 0.06 μg/mL and 0.06 μg/mL to 0.2 μg/mL, respectively. The relative standard deviations (RSDs for intra- and inter-day precisions were below 3.3% and 4.2%, respectively. The mean recovery rates ranged from 96.7% to 104.5% with the relative standard deviations (RSDs less than 2.72%. It is concluded that RRLC-TOF/MS is powerful and practical in qualitative and quantitative analysis of complex plant samples due to time savings, sensitivity, precision, accuracy and lowering solvent consumption.

Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources

International Nuclear Information System (INIS)

David, W.I.F.; Jorgensen, J.D.

1990-10-01

The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument characteristics can be accurately modelled, which make Rietveld refinement possible for complex structures. In this paper we briefly review the development of the Rietveld method for time-of-flight diffraction data from pulsed neutron sources and discuss the latest developments in high resolution instrumentation and advanced Rietveld analysis methods. 50 refs., 12 figs., 14 tabs

Time of flight measurement on the SOFIA experiment

International Nuclear Information System (INIS)

Bail, A.; Taieb, J.; Chatillon, A.; Belier, G.; Laurent, B.; Pellereau, E.

2011-01-01

The SOFIA experiment, which will be held at GSI (Darmstadt (Germany)) will allow to completely determine the mass and charge numbers of fragments produced in the fission reaction of radioactive actinides in reverse kinematics. Therefore, a dedicated setup has been developed for the Time of Flight measurement of relativistic heavy ions. The studies, which led to the choice of the adequate plastic scintillators and photomultipliers, are presented. Tests have been undertaken with the ELSA laser and electron beam facility. They shown that a suitable choice would be EJ-232 plastic scintillator for the ToF wall and EJ-232Q for the start detector and Hamamatsu H6533 and H10580 photomultipliers. This was confirmed by two test experiments realized at GSI with relativistic heavy ion beam ( 56 Fe and 238 U), where a time of flight resolution better than 20 ps FWHM was reached. (authors)

Time of flight measurement on the SOFIA experiment

Energy Technology Data Exchange (ETDEWEB)

Bail, A.; Taieb, J.; Chatillon, A.; Belier, G.; Laurent, B.; Pellereau, E. [CEA/DAM/DIF, Arpajon (France)

2011-07-01

The SOFIA experiment, which will be held at GSI (Darmstadt (Germany)) will allow to completely determine the mass and charge numbers of fragments produced in the fission reaction of radioactive actinides in reverse kinematics. Therefore, a dedicated setup has been developed for the Time of Flight measurement of relativistic heavy ions. The studies, which led to the choice of the adequate plastic scintillators and photomultipliers, are presented. Tests have been undertaken with the ELSA laser and electron beam facility. They shown that a suitable choice would be EJ-232 plastic scintillator for the ToF wall and EJ-232Q for the start detector and Hamamatsu H6533 and H10580 photomultipliers. This was confirmed by two test experiments realized at GSI with relativistic heavy ion beam ({sup 56}Fe and {sup 238}U), where a time of flight resolution better than 20 ps FWHM was reached. (authors)

[Structure identification of contaminants in a beverage product by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry].

Science.gov (United States)

Miyamoto, Yasuhisa; Washida, Kazuto; Uyama, Atsuo; Mochizuki, Naoki

2014-01-01

The contaminants in a beverage product that had been reported to have a strange taste were identified. By comparative analysis with the normal product using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), six unknown compounds were detected in the total ion current chromatograms of the product in question. Detailed analysis of the mass spectra and product ion spectra of these compounds strongly suggested that the compounds were capric acid diethanolamide, lauric acid diethanolamide, myristic acid diethanolamide, lauryl dimethylaminoacetic acid, lauryl sulfate, and lauric acid, all of which are surfactants commonly used as ingredients of household detergents and shampoos. We searched commercially available detergent products to check for the presence of these six surfactants, and identified products that might have been intentionally or unintentionally mixed into the beverage product after opening.

Principle of accelerator mass spectrometry

International Nuclear Information System (INIS)

Matsuzaki, Hiroyuki

2007-01-01

The principle of accelerator mass spectrometry (AMS) is described mainly on technical aspects: hardware construction of AMS, measurement of isotope ratio, sensitivity of measurement (measuring limit), measuring accuracy, and application of data. The content may be summarized as follows: rare isotope (often long-lived radioactive isotope) can be detected by various use of the ion energy obtained by the acceleration of ions, a measurable isotope ratio is one of rare isotope to abundant isotopes, and a measured value of isotope ratio is uncertainty to true one. Such a fact must be kept in mind on the use of AMS data to application research. (M.H.)

Performance of matrix-assisted laser desorption-time of flight mass spectrometry for identification of clinical yeast isolates

DEFF Research Database (Denmark)

Rosenvinge, Flemming S; Dzajic, Esad; Knudsen, Elisa

2013-01-01

Accurate and fast yeast identification is important when treating patients with invasive fungal disease as susceptibility to antifungal agents is highly species related. Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS) provides a powerful tool with a clear potential...... spectra output, all 13 isolates were correctly identified, resulting in an overall identification performance of 92%. No misidentifications occurred with the two systems. Of the routine isolates one laboratory identified 99/99 (100%) and 90/99 (91%) to species level by Saramis/Axima and conventional...... identification, respectively, whereas the other laboratory identified 83/98 (85%) to species level by both BioTyper/Bruker and conventional identification. Both MALDI-TOF-MS systems are fast, have built-in databases that cover the majority of clinically relevant Candida species, and have an accuracy...

Accurate screening for synthetic preservatives in beverage using high performance liquid chromatography with time-of-flight mass spectrometry

International Nuclear Information System (INIS)

Li Xiuqin; Zhang Feng; Sun Yanyan; Yong Wei; Chu Xiaogang; Fang Yanyan; Zweigenbaum, Jerry

2008-01-01

In this study, liquid chromatography time-of-flight mass spectrometry (HPLC/TOF-MS) is applied to qualitation and quantitation of 18 synthetic preservatives in beverage. The identification by HPLC/TOF-MS is accomplished with the accurate mass (the subsequent generated empirical formula) of the protonated molecules [M + H]+ or the deprotonated molecules [M - H]-, along with the accurate mass of their main fragment ions. In order to obtain sufficient sensitivity for quantitation purposes (using the protonated or deprotonated molecule) and additional qualitative mass spectrum information provided by the fragments ions, segment program of fragmentor voltages is designed in positive and negative ion mode, respectively. Accurate mass measurements are highly useful in the complex sample analyses since they allow us to achieve a high degree of specificity, often needed when other interferents are present in the matrix. The mass accuracy typically obtained is routinely better than 3 ppm. The 18 compounds behave linearly in the 0.005-5.0 mg.kg -1 concentration range, with correlation coefficient >0.996. The recoveries at the tested concentrations of 1.0 mg.kg -1 -100 mg.kg -1 are 81-106%, with coefficients of variation -1 , which are far below the required maximum residue level (MRL) for these preservatives in foodstuff. The method is suitable for routine quantitative and qualitative analyses of synthetic preservatives in foodstuff

Analysis of Phospholipid Mixtures from Biological Tissues by Matrix-Assisted Laser Desorption and Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS): A Laboratory Experiment

Science.gov (United States)

Eibisch, Mandy; Fuchs, Beate; Schiller, Jurgen; Sub, Rosmarie; Teuber, Kristin

2011-01-01

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF MS) is increasingly used to investigate the phospholipid (PL) compositions of tissues and body fluids, often without previous separation of the total mixture into the individual PL classes. Therefore, the questions of whether all PL classes are detectable…

Accelerator mass spectrometry and associated facilities at Inter-University Accelerator Centre, New Delhi, India

International Nuclear Information System (INIS)

Kumar, Pankaj; Bohra, Archna; Ojha, S.; Gargari, S.; Joshi, R.; Roonwal, G.S.; Chopra, S.; Pattanaik, J.K.; Balakrishnan, S.

2011-01-01

Accelerator Mass Spectrometry (AMS) facility at Inter-University Accelerator Centre (IUAC) is developed by upgrading its existing 15UD Pelletron accelerator. Since last two decades Pelletron is mainly used for nuclear physics, materials science, atomic physics, radiation biology and accelerator mass spectrometry is recent development. In addition, a chemistry laboratory in clean room for the chemical processing of samples for AMS studies has also been established. At present the AMS facility is used for 10 Be, 26 Al measurements and soon other long lived radio-isotopes will also be used

Structural calculations and experimental detection of small Ga mS n clusters using time-of-flight mass spectrometry

Science.gov (United States)

BelBruno, J. J.; Sanville, E.; Burnin, A.; Muhangi, A. K.; Malyutin, A.

2009-08-01

Ga mS n clusters were generated by laser ablation of a solid sample of Ga 2S 3. The resulting molecules were analyzed in a time-of-flight mass spectrometer. In addition to atomic species, the spectra exhibited evidence for the existence of GaS3+, GaS4+, GaS5+, and GaS6+ clusters. The potential neutral and cationic structures of the observed Ga mS n clusters were computationally investigated using a density-functional approach. Reference is made to the kinetic pathways required for production of clusters from the starting point of the stoichiometric molecule or molecular ion. Cluster atomization enthalpies are compared with bulk values from the literature.

Shock tube/time-of-flight mass spectrometer for high temperature kinetic studies

International Nuclear Information System (INIS)

Tranter, Robert S.; Giri, Binod R.; Kiefer, John H.

2007-01-01

A shock tube (ST) with online, time-of-flight mass spectrometric (TOF-MS) detection has been constructed for the study of elementary reactions at high temperature. The ST and TOF-MS are coupled by a differentially pumped molecular beam sampling interface, which ensures that the samples entering the TOF-MS are not contaminated by gases drawn from the cold end wall thermal boundary layer in the ST. Additionally, the interface allows a large range of postshock pressures to be used in the shock tube while maintaining high vacuum in the TOF-MS. The apparatus and the details of the sampling system are described along with an analysis in which cooling of the sampled gases and minimization of thermal boundary layer effects are discussed. The accuracy of kinetic measurements made with the apparatus has been tested by investigating the thermal unimolecular dissociation of cyclohexene to ethylene and 1,3-butadiene, a well characterized reaction for which considerable literature data that are in good agreement exist. The experiments were performed at nominal reflected shock wave pressures of 600 and 1300 Torr, and temperatures ranging from 1260 to 1430 K. The rate coefficients obtained are compared with the earlier shock tube studies and are found to be in very good agreement. As expected no significant difference is observed in the rate constant between pressures of 600 and 1300 Torr

Applications of accelerator mass spectrometry to nuclear physics and astrophysics

International Nuclear Information System (INIS)

Guo Zhiyu; Zhang Chuan

2002-01-01

As an ultra high sensitive analyzing method, accelerator mass spectrometry is playing an important role in the studies of nuclear physics and astrophysics. The accelerator mass spectrometry (AMS) applications in searching for violation of Pauli exclusion principle and study on supernovae are discussed as examples

Characterization and quantitative analysis of surfactants in textile wastewater by liquid chromatography/quadrupole-time-of-flight mass spectrometry.

Science.gov (United States)

González, Susana; Petrović, Mira; Radetic, Maja; Jovancic, Petar; Ilic, Vesna; Barceló, Damià

2008-05-01

A method based on the application of ultra-performance liquid chromatography (UPLC) coupled to hybrid quadrupole-time-of-flight mass spectrometry (QqTOF-MS) with an electrospray (ESI) interface has been developed for the screening and confirmation of several anionic and non-ionic surfactants: linear alkylbenzenesulfonates (LAS), alkylsulfate (AS), alkylethersulfate (AES), dihexyl sulfosuccinate (DHSS), alcohol ethoxylates (AEOs), coconut diethanolamide (CDEA), nonylphenol ethoxylates (NPEOs), and their degradation products (nonylphenol carboxylate (NPEC), octylphenol carboxylate (OPEC), 4-nonylphenol (NP), 4-octylphenol (OP) and NPEO sulfate (NPEO-SO4). The developed methodology permits reliable quantification combined with a high accuracy confirmation based on the accurate mass of the (de)protonated molecules in the TOFMS mode. For further confirmation of the identity of the detected compounds the QqTOF mode was used. Accurate masses of product ions obtained by performing collision-induced dissociation (CID) of the (de)protonated molecules of parent compounds were matched with the ions obtained for a standard solution. The method was applied for the quantitative analysis and high accuracy confirmation of surfactants in complex mixtures in effluents from the textile industry. Positive identification of the target compounds was based on accurate mass measurement of the base peak, at least one product ion and the LC retention time of the analyte compared with that of a standard. The most frequently surfactants found in these textile effluents were NPEO and NPEO-SO4 in concentrations ranging from 0.93 to 5.68 mg/L for NPEO and 0.06 to 4.30 mg/L for NPEO-SO4. AEOs were also identified.

Rapid identification of bacteria in positive blood culture broths by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Science.gov (United States)

Stevenson, Lindsay G; Drake, Steven K; Murray, Patrick R

2010-02-01

Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is a rapid, accurate method for identifying bacteria and fungi recovered on agar culture media. We report herein a method for the direct identification of bacteria in positive blood culture broths by MALDI-TOF mass spectrometry. A total of 212 positive cultures were examined, representing 32 genera and 60 species or groups. The identification of bacterial isolates by MALDI-TOF mass spectrometry was compared with biochemical testing, and discrepancies were resolved by gene sequencing. No identification (spectral score of blood culture broth. Of the bacteria with a spectral score of > or = 1.7, 162 (95.3%) of 170 isolates were correctly identified. All 8 isolates of Streptococcus mitis were misidentified as being Streptococcus pneumoniae isolates. This method provides a rapid, accurate, definitive identification of bacteria within 1 h of detection in positive blood cultures with the caveat that the identification of S. pneumoniae would have to be confirmed by an alternative test.

Measuring test mass acceleration noise in space-based gravitational wave astronomy

Science.gov (United States)

Congedo, Giuseppe

2015-03-01

The basic constituent of interferometric gravitational wave detectors—the test-mass-to-test-mass interferometric link—behaves as a differential dynamometer measuring effective differential forces, comprising an integrated measure of gravity curvature, inertial effects, as well as nongravitational spurious forces. This last contribution is going to be characterized by the LISA Pathfinder mission, a technology precursor of future space-borne detectors like eLISA. Changing the perspective from displacement to acceleration can benefit the data analysis of LISA Pathfinder and future detectors. The response in differential acceleration to gravitational waves is derived for a space-based detector's interferometric link. The acceleration formalism can also be integrated into time delay interferometry by building up the unequal-arm Michelson differential acceleration combination. The differential acceleration is nominally insensitive to the system's free evolution dominating the slow displacement dynamics of low-frequency detectors. Working with acceleration also provides an effective way to subtract measured signals acting as systematics, including the actuation forces. Because of the strong similarity with the equations of motion, the optimal subtraction of systematic signals, known within some amplitude and time shift, with the focus on measuring the noise provides an effective way to solve the problem and marginalize over nuisance parameters. The F statistic, in widespread use throughout the gravitation waves community, is included in the method and suitably generalized to marginalize over linear parameters and noise at the same time. The method is applied to LPF simulator data and, thanks to its generality, can also be applied to the data reduction and analysis of future gravitational wave detectors.

Linear electric field time-of-flight ion mass spectrometer

Science.gov (United States)

Funsten, Herbert O [Los Alamos, NM; Feldman, William C [Los Alamos, NM

2008-06-10

A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

New Potential Biomarker for Methasterone Misuse in Human Urine by Liquid Chromatography Quadrupole Time of Flight Mass Spectrometry.

Science.gov (United States)

Zhang, Jianli; Lu, Jianghai; Wu, Yun; Wang, Xiaobing; Xu, Youxuan; Zhang, Yinong; Wang, Yan

2016-09-24

In this study, methasterone urinary metabolic profiles were investigated by liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF-MS) in full scan and targeted MS/MS modes with accurate mass measurement. A healthy male volunteer was asked to take the drug and liquid-liquid extraction was employed to process urine samples. Chromatographic peaks for potential metabolites were hunted out with the theoretical [M - H](-) as a target ion in a full scan experiment and actual deprotonated ions were studied in targeted MS/MS experiment. Fifteen metabolites including two new sulfates (S1 and S2), three glucuronide conjugates (G2, G6 and G7), and three free metabolites (M2, M4 and M6) were detected for methasterone. Three metabolites involving G4, G5 and M5 were obtained for the first time in human urine samples. Owing to the absence of helpful fragments to elucidate the steroid ring structure of methasterone phase II metabolites, gas chromatography mass spectrometry (GC-MS) was employed to obtain structural information of the trimethylsilylated phase I metabolite released after enzymatic hydrolysis and the potential structure was inferred using a combined MS method. Metabolite detection times were also analyzed and G2 (18-nor-17β-hydroxymethyl-2α, 17α-dimethyl-androst-13-en-3α-ol-ξ-O-glucuronide) was thought to be new potential biomarker for methasterone misuse which can be detected up to 10 days.

In cleanroom, sub-ppb real-time monitoring of volatile organic compounds using proton-transfer reaction/time of flight/mass spectrometry

Science.gov (United States)

Hayeck, Nathalie; Maillot, Philippe; Vitrani, Thomas; Pic, Nicolas; Wortham, Henri; Gligorovski, Sasho; Temime-Roussel, Brice; Mizzi, Aurélie; Poulet, Irène

2014-04-01

Refractory compounds such as Trimethylsilanol (TMS) and other organic compounds such as propylene glycol methyl ether acetate (PGMEA) used in the photolithography area of microelectronic cleanrooms have irreversible dramatic impact on optical lenses used on photolithography tools. There is a need for real-time, continuous measurements of organic contaminants in representative cleanroom environment especially in lithography zone. Such information is essential to properly evaluate the impact of organic contamination on optical lenses. In this study, a Proton-Transfer Reaction-Time-of-Flight Mass spectrometer (PTR-TOF-MS) was applied for real-time and continuous monitoring of fugitive organic contamination induced by the fabrication process. Three types of measurements were carried out using the PTR-TOF-MS in order to detect the volatile organic compounds (VOCs) next to the tools in the photolithography area and at the upstream and downstream of chemical filters used to purge the air in the cleanroom environment. A validation and verification of the results obtained with PTR-TOF-MS was performed by comparing these results with those obtained with an off-line technique that is Automated Thermal Desorber - Gas Chromatography - Mass Spectrometry (ATD-GC-MS) used as a reference analytical method. The emerged results from the PTR-TOF-MS analysis exhibited the temporal variation of the VOCs levels in the cleanroom environment during the fabrication process. While comparing the results emerging from the two techniques, a good agreement was found between the results obtained with PTR-TOF-MS and those obtained with ATD-GC-MS for the PGMEA, toluene and xylene. Regarding TMS, a significant difference was observed ascribed to the technical performance of both instruments.

Time-of-flight mass spectrometry of laser exploding foil initiated PETN samples

Science.gov (United States)

Fajardo, Mario E.; Molek, Christopher D.; Fossum, Emily C.

2017-01-01

We report the results of time-of-flight mass spectrometry (TOFMS) measurements of the gaseous products of thin-film pentaerythritol tetranitrate [PETN, C(CH2NO3)4] samples reacting in vacuo. The PETN sample spots are produced by masked physical vapor deposition [A.S. Tappan, et al., AIP Conf. Proc. 1426, 677 (2012)] onto a first-surface aluminum mirror. A pulsed laser beam imaged through the soda lime glass mirror substrate converts the aluminum layer into a high-temperature high-pressure plasma which initiates chemical reactions in the overlying PETN sample. We had previously proposed [E.C. Fossum, et al., AIP Conf. Proc. 1426, 235 (2012)] to exploit differences in gaseous product chemical identities and molecular velocities to provide a chemically-based diagnostic for distinguishing between "detonation-like" and deflagration responses. Briefly: we expect in-vacuum detonations to produce hyperthermal (v˜10 km/s) thermodynamically-stable products such as N2, CO2, and H2O, and for deflagrations to produce mostly reaction intermediates, such as NO and NO2, with much slower molecular velocities - consistent with the expansion-quenched thermal decomposition of PETN. We observe primarily slow reaction intermediates (NO2, CH2NO3) at low laser pulse energies, the appearance of NO at intermediate laser pulse energies, and the appearance of hyperthemal CO/N2 at mass 28 amu at the highest laser pulse energies. However, these results are somewhat ambiguous, as the NO, NO2, and CH2NO3 intermediates persist and all species become hyperthermal at the higher laser pulse energies. Also, the purported CO/N2 signal at 28 amu may be contaminated by silicon ablated from the glass mirror substrate. We plan to mitigate these problems in future experiments by adopting the "Buelow" sample configuration which employs an intermediate foil barrier to shield the energetic material from the laser and the laser driven plasma [S.J. Buelow, et al., AIP Conf. Proc. 706, 1377 (2003)].

Laser sputter neutral mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

King, B.V.; Clarke, M.; Hu, H.; Betz [Newcastle Univ., NSW (Australia). Dept. of Physics

1993-12-31

Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

Laser sputter neutral mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

King, B V; Clarke, M; Hu, H; Betz, [Newcastle Univ., NSW (Australia). Dept. of Physics

1994-12-31

Laser sputter neutral mass spectrometry (LSNMS) is an emerging technique for highly sensitive surface analysis. In this technique a target is bombarded with a pulsed beam of keV ions. The sputtered particles are intercepted by a high intensity pulsed laser beam above the surface and ionised with almost 100% efficiency. The photions may then be mass analysed using a quadrupole or, more commonly, using time of flight (TOF) techniques. In this method photoions are extracted from the ionisation region, accelerated to a known energy E{sub o} and strike a channelplate detector a distance `d` away. The flight time `t` of the photoions is then related to their mass by `d` {radical}m / {radical} 2E{sub o} so measurement of `t` allows mass spectra to be obtained. It is found that LSNMS is an emerging technique of great sensitivity and flexibility, useful for both applied analysis and to investigate basic sputtering processes. 4 refs., 3 figs.

Mass, charge, and energy separation by selective acceleration with a traveling potential hill

Science.gov (United States)

Tung, L. Schwager; Barr, W. L.; Lowder, R. S.; Post, R. F.

1996-10-01

A traveling electric potential hill has been used to generate an ion beam with an energy distribution that is mass dependent from a monoenergetic ion beam of mixed masses. This effect can be utilized as a novel method for mass separation applied to identification or enrichment of ions (e.g., of elements, isotopes, or molecules). This theory for mass-selective acceleration is presented here and is shown to be confirmed by experiment and by a time-dependent particle-in-cell computer simulation. Results show that monoenergetic ions with the particular mass of choice are accelerated by controlling the hill potential and the hill velocity. The hill velocity is typically 20%-30% faster than the ions to be accelerated. The ability of the hill to pickup a particular mass uses the fact that small kinetic energy differences in the lab frame appear much larger in the moving hill frame. Ions will gain energy from the approaching hill if their relative energy in the moving hill frame is less than the peak potential of the hill. The final energy of these accelerated ions can be several times the source energy, which facilitates energy filtering for mass purification or identification. If the hill potential is chosen to accelerate multiple masses, the heaviest mass will have the greatest final energy. Hence, choosing the appropriate hill potential and collector retarding voltage will isolate ions with the lightest, heaviest, or intermediate mass. In the experimental device, called a Solitron, purified 20Ne and 22Ne are extracted from a ribbon beam of neon that is originally composed of 20Ne:22Ne in the natural ratio of 91:9. The isotopic content of the processed beam is determined by measuring the energy distribution of the detected current. These results agree with the theory. In addition to mass selectivity, our theory can also be applied to the filtration of an ion beam according to charge state or energy. Because of this variety of properties, the Solitron is envisioned to

Observations of the Coronal Mass Ejection with a Complex Acceleration Profile

Science.gov (United States)

Reva, A. A.; Kirichenko, A. S.; Ulyanov, A. S.; Kuzin, S. V.

2017-12-01

We study the coronal mass ejection (CME) with a complex acceleration profile. The event occurred on 2009 April 23. It had an impulsive acceleration phase, an impulsive deceleration phase, and a second impulsive acceleration phase. During its evolution, the CME showed signatures of different acceleration mechanisms: kink instability, prominence drainage, flare reconnection, and a CME–CME collision. The special feature of the observations is the usage of the TESIS EUV telescope. The instrument could image the solar corona in the Fe 171 Å line up to a distance of 2 {R}ȯ from the center of the Sun. This allows us to trace the CME up to the LASCO/C2 field of view without losing the CME from sight. The onset of the CME was caused by kink instability. The mass drainage occurred after the kink instability. The mass drainage played only an auxiliary role: it decreased the CME mass, which helped to accelerate the CME. The first impulsive acceleration phase was caused by the flare reconnection. We observed the two-ribbon flare and an increase of the soft X-ray flux during the first impulsive acceleration phase. The impulsive deceleration and the second impulsive acceleration phases were caused by the CME–CME collision. The studied event shows that CMEs are complex phenomena that cannot be explained with only one acceleration mechanism. We should seek a combination of different mechanisms that accelerate CMEs at different stages of their evolution.

Determination of Power Required through Accelerated Flight with Application to Unmanned Vehicles

Science.gov (United States)

Soltmann, Lars Michael

for comparison against the dynamic method. The results show good agreement between the deceleration runs and the PIW-VIW method for both aircraft. The acceleration runs generally had a poorer overall fit and a larger spread. This is due to excessive sensor noise caused by vibrations from the propulsion system. The acceleration runs were also more difficult to perform as the pilot was not always able to keep the thrust-induced pitching effects low during throttle up. A throttle ramp up was performed in an attempt to mitigate this effect and improve data quality; however, the analysis revealed no difference in the resulting power curves. Overall the dynamic power analysis was found to be a valid analysis tool for power required, especially when the deceleration run was used. Besides the decreased noise over the acceleration run, the deceleration run offers the advantage of neglecting the thrust model, especially when using aircraft with electric propulsion systems since they can be turned off in flight resulting in zero residual thrust. This improves the accuracy of the resulting power required curves as well as saving time and effort since wind tunnel testing for propeller model generation can be avoided.

Simultaneous determination of niacin and pyridoxine at trace levels by using diode array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry.

Science.gov (United States)

Sel, Sabriye; Öztürk Er, Elif; Bakırdere, Sezgin

2017-12-01

A highly sensitive and simple diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method was developed for the simultaneous determination of niacin and pyridoxine in pharmaceutical drugs, tap water, and wastewater samples. To determine the in vivo behavior of niacin and pyridoxine, analytes were subjected to simulated gastric conditions. The calibration plots of the diode-array high-performance liquid chromatography and liquid chromatography with quadrupole time-of-flight tandem mass spectrometry method showed good linearity over a wide concentration range with close to 1.0 correlation coefficients for both analytes. The limit of detection/limit of quantitation values for liquid chromatography quadrupole time-of-flight tandem mass spectrometry analysis were 1.98/6.59 and 1.3/4.4 μg/L for niacin and pyridoxine, respectively, while limit of detection/limit of quantitation values for niacin and pyridoxine in high-performance liquid chromatography analysis were 3.7/12.3 and 5.7/18.9 μg/L, respectively. Recovery studies were also performed to show the applicability of the developed methods, and percentage recovery values were found to be 90-105% in tap water and 94-97% in wastewater for both analytes. The method was also successfully applied for the qualitative and quantitative determination of niacin and pyridoxine in drug samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantification, confirmation and screening capability of UHPLC coupled to triple quadrupole and hybrid quadrupole time-of-flight mass spectrometry in pesticide residue analysis.

Science.gov (United States)

Grimalt, Susana; Sancho, Juan V; Pozo, Oscar J; Hernández, Félix

2010-04-01

The potential of three mass spectrometry (MS) analyzers (triple quadrupole, QqQ; time of flight, TOF; and quadrupole time of flight, QTOF) has been investigated and compared for quantification, confirmation and screening purposes in pesticide residue analysis of fruit and vegetable samples. For this purpose, analytical methodology for multiresidue determination of 11 pesticides, taken as a model, has been developed and validated in nine food matrices for the three mass analyzers coupled to ultra high pressure liquid chromatography. In all cases, limits of quantification around 0.01 mg/kg were reached, fulfilling the most restrictive case of baby-food analysis. Regarding absolute sensitivity, the lower limits of detection were obtained, as expected, for QqQ (100 fg), whereas slightly higher limits (300 fg) were obtained for both TOF and QTOF. Confirmative capacity of each analyzer was studied for each analyte based on the identification points (IPs) criterion, useful for a comprehensive comparison. QTOF mass analyzer showed the highest confirmatory capacity, although QqQ normally led to sufficient number of IPs, even at lower concentration levels. The potential of TOF MS was also investigated for screening purposes. To this aim, around 50 commercial fruits and vegetables samples were analyzed, searching for more than 400 pesticides. TOF MS proved to be an attractive analytical tool for rapid detection and reliable identification of a large number of pesticides thanks to the full spectrum acquisition at accurate mass with satisfactory sensitivity. This process is readily boosted when combined with specialized software packages, together with theoretical exact mass databases. Several pesticides (e.g. carbendazim in citrus and indoxacarb in grape) were detected in the samples. Further unequivocal confirmation of the identity was performed using reference standards and/or QTOF MS/MS experiments. Copyright 2010 John Wiley & Sons, Ltd.

On the elemental analysis of different cigarette brands using laser induced breakdown spectroscopy and laser-ablation time of flight mass spectrometry

Science.gov (United States)

Ahmed, Nasar; Umar, Zeshan A.; Ahmed, Rizwan; Aslam Baig, M.

2017-10-01

We present qualitative and quantitative analysis of the trace elements present in different brands of tobacco available in Pakistan using laser induced breakdown spectroscopy (LIBS) and Laser ablation Time of Flight Mass Spectrometer (LA-TOFMS). The compositional analysis using the calibration free LIBS technique is based on the observed emission spectra of the laser produced plasma plume whereas the elemental composition analysis using LA-TOFMS is based on the mass spectra of the ions produced by laser ablation. The optical emission spectra of these samples contain spectral lines of calcium, magnesium, sodium, potassium, silicon, strontium, barium, lithium and aluminum with varying intensities. The corresponding mass spectra of the elements were detected in LA-TOF-MS with their composition concentration. The analysis of different brands of cigarettes demonstrates that LIBS coupled with a LA-TOF-MS is a powerful technique for the elemental analysis of the trace elements in any solid sample.

A statistical investigation of the mass discrepancy-acceleration relation

Science.gov (United States)

Desmond, Harry

2017-02-01

We use the mass discrepancy-acceleration relation (the correlation between the ratio of total-to-visible mass and acceleration in galaxies; MDAR) to test the galaxy-halo connection. We analyse the MDAR using a set of 16 statistics that quantify its four most important features: shape, scatter, the presence of a `characteristic acceleration scale', and the correlation of its residuals with other galaxy properties. We construct an empirical framework for the galaxy-halo connection in LCDM to generate predictions for these statistics, starting with conventional correlations (halo abundance matching; AM) and introducing more where required. Comparing to the SPARC data, we find that: (1) the approximate shape of the MDAR is readily reproduced by AM, and there is no evidence that the acceleration at which dark matter becomes negligible has less spread in the data than in AM mocks; (2) even under conservative assumptions, AM significantly overpredicts the scatter in the relation and its normalization at low acceleration, and furthermore positions dark matter too close to galaxies' centres on average; (3) the MDAR affords 2σ evidence for an anticorrelation of galaxy size and Hubble type with halo mass or concentration at fixed stellar mass. Our analysis lays the groundwork for a bottom-up determination of the galaxy-halo connection from relations such as the MDAR, provides concrete statistical tests for specific galaxy formation models, and brings into sharper focus the relative evidence accorded by galaxy kinematics to LCDM and modified gravity alternatives.

Detection of over 100 selenium metabolites in selenized yeast by liquid chromatography electrospray time-of-flight mass spectrometry.

Science.gov (United States)

Gilbert-López, Bienvenida; Dernovics, Mihaly; Moreno-González, David; Molina-Díaz, Antonio; García-Reyes, Juan F

2017-08-15

The characterization of the selenometabolome of Selenized(Se)-yeast, that is the fraction of water soluble low-molecular weight Se-metabolites produced in Se-yeast is of paramount interest to expand the knowledge on the composition of this food supplement. In this work, we have applied liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS) to search for Se-species from the low molecular weight range fraction of the selenized yeast used for food supplements. Prior to LC-TOFMS, sample treatment consisted of ultrasound assisted water extraction followed by size exclusion fractionation assisted with off-line inductively coupled plasma mass spectrometry detection of isotope 82 Se. The fraction corresponding to low-molecular weight species was subjected to LC-TOFMS using electrospray ionization in the positive ion mode. The detection of the suspected selenized species has been based on the information obtained from accurate mass measurements of both the protonated molecules and fragments from in-source CID fragmentation; along with the characteristic isotope pattern exhibited by the presence of Se. The approach enables the detection of 103 selenized species, most of them not previously reported, in the range from ca. 300-650Da. Besides the detection of selenium species, related sulphur derivate metabolites were detected based on the accurate mass shift due to the substitution of sulphur and selenium. Copyright © 2017. Published by Elsevier B.V.

Accelerator mass spectrometry for measurement of long-lived radioisotopes.

Science.gov (United States)

Elmore, D; Phillips, F M

1987-05-01

Particle accelerators, such as those built for research in nuclear physics, can also be used together with magnetic and electrostatic mass analyzers to measure rare isotopes at very low abundance ratios. All molecular ions can be eliminated when accelerated to energies of millions of electron volts. Some atomic isobars can be eliminated with the use of negative ions; others can be separated at high energies by measuring their rate of energy loss in a detector. The long-lived radioisotopes (10)Be, (14)C,(26)A1, 36Cl, and (129)1 can now be measured in small natural samples having isotopic abundances in the range 10(-12) to 10(- 5) and as few as 10(5) atoms. In the past few years, research applications of accelerator mass spectrometry have been concentrated in the earth sciences (climatology, cosmochemistry, environmental chemistry, geochronology, glaciology, hydrology, igneous petrogenesis, minerals exploration, sedimentology, and volcanology), in anthropology and archeology (radiocarbon dating), and in physics (searches for exotic particles and measurement of halflives). In addition, accelerator mass spectrometry may become an important tool for the materials and biological sciences.

Importance of the virtual mass force in accelerating steam/water mixtures

International Nuclear Information System (INIS)

Khalil, Y.F.; Kazimi, M.S.

1987-01-01

Virtual mass force is one of the forces that must be considered against accelerating a dispersed fluid flowing in the bulk of a continuous fluid. This force depends on the geometry of the interface and the flow pattern of the two fluids. For dilute two-phase flow mixtures where the bubbles are singly dispersed, the value of the virtual mass force coefficient is dependent on the geometry of the bubble. However, for high void fraction cases, such as depressurization initiated by a pipe break in light water reactors, more intense interaction is expected between the two phase and, therefore, the value of the virtual mass force must be well defined. The effects of implementing the virtual mass force term in the momentum equations of a two-fluid model may be significant for improving the stability of the solution of the conservation equations, the accuracy of the numerical results, and the computation time. In the current work, a new stability criterion is derived after implementing Hancox's model for the virtual mass force in the momentum equations of the six-equation two-phase flow model of TERMIT. A one-dimensional blow-down in a horizontal pipe is considered to investigate the importance of incorporating the virtual mass force in accelerating mixtures flows

Time of flight spectrometry in heavy ions backscattering analysis

International Nuclear Information System (INIS)

Chevarier, A.; Chevarier, N.

1983-05-01

Time of flight spectrometry for backscattering analysis of MeV heavy ions is proposed. The capabilities and limitations of this method are investigated. Depth and mass resolution obtained in measurements of oxide films thickness as well as in GaAs layers analysis are presented. The importance of minimizing pile-up without significant loss of resolution by use of an adequate absorber set just in front of the rear detector is underlined

Design, simulations and test of a Time-of-Flight spectrometer for mass measurement of exotic beams from SPIRAL1/SPIRAL2 and γ-ray spectroscopy of N=Z nuclei close to 100Sn

International Nuclear Information System (INIS)

Chauveau, Pierre

2016-01-01

The new generation of nuclear facilities calls for new technological developments to produce, accelerate, manipulate and analyse exotic nuclei. The main topic of this thesis work was the simulation, design and test of a Multi-Reflection Time-of-Flight Mass spectrometer (MR-ToFMS) for fast mass separation and fast mass measurement of radioactive ions in the installations S3 and DESIR at SPIRAL2. Such a device could separate isobaric nuclei and provide SPIRAL2 with high purity beams. Also, its mass measurement capabilities would help to determine binding energies of exotic and superheavy nuclei with a high precision. This apparatus has been simulated with the SIMION 8.1 software and designed accordingly. First offline tests have been performed with a stable ion source at LPC Caen. In addition a low-aberration electrostatic deflector has been simulated and designed to operate with this MR-ToF-MS without spoiling its performances. This work also describes the analysis and results of the first online tests of a FEBIAD-type ion source intended to provide SPIRAL1 and SPIRAL2 radioactive beams of competitive intensities. Finally, we describe the analysis of a nuclear physics experiment, including the calibration of the different detectors and the gamma-spectroscopy of nuclei in the vicinity of the doubly magic 100 Sn. (author) [fr

Evaluation of matrix-assisted laser desorption/ionization time of flight mass spectrometry for the identification of ceratopogonid and culicid larvae.

Science.gov (United States)

Steinmann, I C; Pflüger, V; Schaffner, F; Mathis, A; Kaufmann, C

2013-03-01

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was evaluated for the rapid identification of ceratopogonid larvae. Optimal sample preparation as evaluated with laboratory-reared biting midges Culicoides nubeculosus was the homogenization of gut-less larvae in 10% formic acid, and analysis of 0.2 mg/ml crude protein homogenate mixed with SA matrix at a ratio of 1:1.5. Using 5 larvae each of 4 ceratopogonid species (C. nubeculosus, C. obsoletus, C. decor, and Dasyhelea sp.) and of 2 culicid species (Aedes aegypti, Ae. japonicus), biomarker mass sets between 27 and 33 masses were determined. In a validation study, 67 larvae belonging to the target species were correctly identified by automated database-based identification (91%) or manual full comparison (9%). Four specimens of non-target species did not yield identification. As anticipated for holometabolous insects, the biomarker mass sets of adults cannot be used for the identification of larvae, and vice versa, because they share only very few similar masses as shown for C. nubeculosus, C. obsoletus, and Ae. japonicus. Thus, protein profiling by MALDI-TOF as a quick, inexpensive and accurate alternative tool is applicable to identify insect larvae of vector species collected in the field.

Analysis of drugs of forensic interest with capillary zone electrophoresis/time-of-flight mass spectrometry based on the use of non-volatile buffers.

Science.gov (United States)

Gottardo, Rossella; Mikšík, Ivan; Aturki, Zeineb; Sorio, Daniela; Seri, Catia; Fanali, Salvatore; Tagliaro, Franco

2012-02-01

The present work is aimed at investigating the influence of the background electrolyte composition and concentration on the separation efficiency and resolution and mass spectrometric detection of illicit drugs in a capillary zone electrophoresis-electrospray ionization-time of flight mass spectrometry (CZE-ESI-TOF MS) system. The effect of phosphate, borate and Tris buffers on the separation and mass spectrometry response of a mixture of 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine and 6-monoacetylmorphine was studied, in comparison with a reference ammonium formate separation buffer. Inorganic non-volatile borate and Tris buffers proved hardly suitable for capillary electrophoresis-mass spectrometry (CE-MS) analysis, but quite unexpectedly ammonium phosphate buffers showed good separation and ionization performances for all the analytes tested. Applications of this method to real samples of hair from drug addicts are also provided. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid Identification of Intact Staphylococcal Bacteriophages Using Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry

Directory of Open Access Journals (Sweden)

Dana Štveráková

2018-04-01

Full Text Available Staphylococcus aureus is a major causative agent of infections associated with hospital environments, where antibiotic-resistant strains have emerged as a significant threat. Phage therapy could offer a safe and effective alternative to antibiotics. Phage preparations should comply with quality and safety requirements; therefore, it is important to develop efficient production control technologies. This study was conducted to develop and evaluate a rapid and reliable method for identifying staphylococcal bacteriophages, based on detecting their specific proteins using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS profiling that is among the suggested methods for meeting the regulations of pharmaceutical authorities. Five different phage purification techniques were tested in combination with two MALDI-TOF MS matrices. Phages, either purified by CsCl density gradient centrifugation or as resuspended phage pellets, yielded mass spectra with the highest information value if ferulic acid was used as the MALDI matrix. Phage tail and capsid proteins yielded the strongest signals whereas the culture conditions had no effect on mass spectral quality. Thirty-seven phages from Myoviridae, Siphoviridae or Podoviridae families were analysed, including 23 siphophages belonging to the International Typing Set for human strains of S. aureus, as well as phages in preparations produced by Microgen, Bohemia Pharmaceuticals and MB Pharma. The data obtained demonstrate that MALDI-TOF MS can be used to effectively distinguish between Staphylococcus-specific bacteriophages.

Method for the elucidation of the elemental composition of low molecular mass chemicals using exact masses of product ions and neutral losses: application to environmental chemicals measured by liquid chromatography with hybrid quadrupole/time-of-flight mass spectrometry.

Science.gov (United States)

Suzuki, Shigeru; Ishii, Tetsuko; Yasuhara, Akio; Sakai, Shinichi

2005-01-01

A method for elucidating the elemental compositions of low molecular weight chemicals, based primarily on mass measurements made using liquid chromatography (LC) with time-of-flight mass spectrometry (TOFMS) and quadrupole/time-of-flight mass spectrometry (LC/QTOFMS), was developed and tested for 113 chemicals of environmental interest with molecular masses up to approximately 400 Da. As the algorithm incorporating the method is not affected by differences in the instrument used, or by the ionization method and other ionization conditions, the method is useful not only for LC/TOFMS, but also for all kinds of mass spectra measured with higher accuracy and precision (uncertainties of a few mDa) employing all ionization methods and on-line separation techniques. The method involves calculating candidate compositions for intact ionized molecules (ionized forms of the sample molecule that have lost or gained no more than a proton, i.e., [M+H](+) or [M-H](-)) as well as for fragment ions and corresponding neutral losses, and eliminating those atomic compositions for the molecules that are inconsistent with the corresponding candidate compositions of fragment ions and neutral losses. Candidate compositions were calculated for the measured masses of the intact ionized molecules and of the fragment ions and corresponding neutral losses, using mass uncertainties of 2 and 5 mDa, respectively. Compositions proposed for the ionized molecule that did not correspond to the sum of the compositions of a candidate fragment ion and its corresponding neutral loss were discarded. One, 2-5, 6-10, 11-20, and >20 candidate compositions were found for 65%, 39%, 1%, 1%, and 0%, respectively, for the 124 ionized molecules formed from the 113 chemicals tested (both positive and negative ions were obtained from 11 of the chemicals). However, no candidate composition was found for 2% of the test cases (i.e., 3 chemicals), for each of which the measured mass of one of the product ions was in

The future of the accelerator mass spectrometry of rare long-lived radioactive isotopes

International Nuclear Information System (INIS)

Litherland, A.E.

1990-01-01

Accelerators, originally designed for nuclear physics, can be added to mass spectrometric apparatus to increase the sensitivity so that isotope ratios in the range 10 -12 to 10 -15 can be measured routinely. This significant improvement of high-sensitivity mass spectrometry has been called Accelerator Mass Spectrometry. The present article addresses the basic principles of accelerator mass spectrometry and some recent applications which show its versatility. In particular, it is noted that accelerator mass spectrometry could play an increasing role in the measurement of the levels of long lived radioactivities in the environment, including the actinides, which result from human activities such as the use of nuclear power. To fulfill this promise, continued research and development is necessary to provide ion sources, various types of heavy ion accelerators and peripheral magnetic and electric analysers. (N.K.)

Determination of sildenafil mixed into herbal honey mixture by ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry

Directory of Open Access Journals (Sweden)

Neira Mustabasic

2017-01-01

Full Text Available There has been a number of reports of natural products contaminated with illegal adulterants that threaten consumer health because of their adverse pharmacological effects worldwide. In this study, a multi-residual ultra-performance liquid chromatography method with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS was applied for the identification of sildenafil added into a herbal honey mixture used as an immune system booster. Electrospray ionization (ESI source was applied and operated in the positive ion mode. The mobile phase consisted of 0.1% formic acid aqueous solution/acetonitrile (70:30, v/v using the isocratic gradient elution system at a detection wavelength of 290 nm. The compound of sildenafil added into traditional herbal mixed honey was identified according to the spectrum, chromatographic behavior, and mass spectral data were identified by comparison with the reference substance. The method is selective, sensitive and can be used to detect the sildenafil illegally added into traditional herbal medicinal preparations.

Measurement of detector neutron energy response using time-of-flight techniques

International Nuclear Information System (INIS)

Janee, H.S.

1973-09-01

The feasibility of using time-of-flight techniques at the EG and G/AEC linear accelerator for measuring the neutron response of relatively sensitive detectors over the energy range 0.5 to 14 MeV has been demonstrated. The measurement technique is described in detail as are the results of neutron spectrum measurements from beryllium and uranium photoneutron targets. The sensitivity of a fluor photomultiplier LASL detector with a 2- by 1-inch NE-111 scintillator was determined with the two targets, and agreement in the region of overlap was very good. (U.S.)

Identification of berberrubine metabolites in rats by using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

Science.gov (United States)

Wang, Kun; Qiao, Miao; Chai, Liwei; Cao, Shijie; Feng, Xinchi; Ding, Liqin; Qiu, Feng

2018-01-01

Berberrubine, an isoquinoline alkaloid isolated from many medicinal plants, possesses diverse pharmacological activities, including glucose-lowering, lipid-lowering, anti-inflammatory, and anti-tumor effects. This study aimed to investigate the metabolic profile of berberrubine in vivo. Therefore, a rapid and reliable method using the ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and metabolynx™ software with mass defect filter (MDF) technique was developed. Plasma, bile, urine and feces samples were collected from rats after oral administration of berberrubine with a dose of 30.0mg/kg and analyzed to characterize the metabolites of berberrubine in vivo for the first time. A total of 57 metabolites were identified, including 54 metabolites in urine, 39 metabolites in plasma, 28 metabolites in bile and 18 metabolites in feces. The results indicated that demethylenation, reduction, hydroxylation, demethylation, glucuronidation, and sulfation were the major metabolic pathways of berberrubine in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

Eddy covariance emission and deposition flux measurements using proton transfer reaction – time of flight – mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes

NARCIS (Netherlands)

Park, J.H.; Goldstein, A.H.; Timkovsky, J|info:eu-repo/dai/nl/330541676; Fares, S.; Weber, R.; Karlik, J.; Holzinger, R.|info:eu-repo/dai/nl/337989338

2013-01-01

During summer 2010, a proton transfer reaction – time of flight – mass spectrometer (PTR-TOF-MS) and a quadrupole proton transfer reaction mass spectrometer (PTR-MS) were deployed simultaneously for one month in an orange orchard in the Central Valley of California to collect continuous data

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

Energy Technology Data Exchange (ETDEWEB)

Machado, Maria Elisabete; Cappelli Fontanive, Fernando; Bastos Caramao, Elina; Alcaraz Zini, Claudia [Universidade Federal do Rio Grande do Sul, Instituto de Quimica, Porto Alegre, RS (Brazil); Oliveira, Jose Vladimir de [URI, Universidade Regional Integrada do Alto Uruguai e das Missoes, Erechim, RS (Brazil)

2011-11-15

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

Use of electron ionization and atmospheric pressure chemical ionization in gas chromatography coupled to time-of-flight mass spetrometry for screening and identification of organic pollutants in waters

NARCIS (Netherlands)

Portoles, T.; Mol, J.G.J.; Sancho, J.V.; Hernandez, F.

2014-01-01

A new approach has been developed for multiclass screening of organic contaminants in water based on the use of gas chromatography coupled to hybrid quadrupole high-resolution time-of-flight mass spectrometry with atmospheric pressure chemical ionization (GC–(APCI)QTOF MS). The soft ionization

Robust flight control using incremental nonlinear dynamic inversion and angular acceleration prediction

NARCIS (Netherlands)

Sieberling, S.; Chu, Q.P.; Mulder, J.A.

2010-01-01

This paper presents a flight control strategy based on nonlinear dynamic inversion. The approach presented, called incremental nonlinear dynamic inversion, uses properties of general mechanical systems and nonlinear dynamic inversion by feeding back angular accelerations. Theoretically, feedback of

Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures

DEFF Research Database (Denmark)

Cereser, Alberto; Strobl, Markus; Hall, Stephen A.

2017-01-01

constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND......-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure...

Analytical detection of explosives and illicit, prescribed and designer drugs using proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS)

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Bishu; Petersson, Fredrik; Juerschik, Simone [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); Sulzer, Philipp; Jordan, Alfons [IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck (Austria); Maerk, Tilmann D. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck (Austria); Watts, Peter; Mayhew, Chris A. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 4TT (United Kingdom)

2011-07-01

This work demonstrates the extremely favorable features of Proton Transfer Reaction Time-of-flight Mass Spectrometry (PTR-TOF-MS) for the detection and identification of solid explosives, chemical warfare agent simulants and illicit, prescribed and designer drugs in real time. Here, we report the use of PTR-TOF, for the detection of explosives (e.g., trinitrotoluene, trinitrobenzene) and illicit, prescribed and designer drugs (e.g., ecstasy, morphine, heroin, ethcathinone, 2C-D). For all substances, the protonated parent ion (as we used H{sub 3}O{sup +} as a reagent ion) could be detected, providing a high level of confidence in their identification since the high mass resolution allows compounds having the same nominal mass to be separated. We varied the E/N from 90 to 220 T{sub d} (1 T{sub d}=10{sup -17} Vcm{sup -1}). This allowed us to study fragmentation pathways as a function of E/N (reduced electric field). For a few compounds rather unusual E/N dependencies were also discovered.

Improved fatty acid detection in micro-algae and aquatic meiofauna species using a direct thermal desorption interface combined with comprehensive gas chromatography-time-of-flight mass spectrometry

NARCIS (Netherlands)

Akoto, L.; Stellaard, F.; Irth, H.; Vreuls, R.J.J.; Pel, R.

2008-01-01

Comprehensive two-dimensional gas chromatography (GC × GC) with time-of-flight mass spectrometry detection is used to profile the fatty acid composition of whole/intact aquatic microorganisms such as the common fresh water green algae Scenedesmus acutus and the filamentous cyanobacterium Limnothrix

Improved fatty acid detection in micro-algae and aquatic meiofauna species using a direct thermal desorption interface combined with comprehensive gas chromatography–time-of-flight mass spectrometry

NARCIS (Netherlands)

Akoto, L.; Stellaard, F.; Irth, H.; Vreuls, R.J.J.; Pel, R.

2008-01-01

Comprehensive two-dimensional gas chromatography (GC × GC) with time-of-flight mass spectrometry detection is used to profile the fatty acid composition of whole/intact aquatic microorganisms such as the common fresh water green algae Scenedesmus acutus and the filamentous cyanobacterium Limnothrix

Improved fatty acid detection in micro-algae and aquatic meiofauna species using a direct thermal desorption interface combined with comprehensive gas chromatography-time-of-flight mass spectrometry

NARCIS (Netherlands)

Akoto, Lawrence; Stellaard, Frans; Irth, Hubertus; Vreuls, Rene J. J.; Pel, Roel

2008-01-01

Comprehensive two-dimensional gas chromatography (GC x GC) with time-of-flight mass spectrometry detection is used to profile the fatty acid composition of whole/intact aquatic microorganisms such as the common fresh water green algae Scenedesmus acutus and the filamentous cyanobacterium Limnothrix

The Time-Of-Flight detector of ALICE at LHC: construction, test and commissioning with cosmic rays

CERN Document Server

Preghenella, Roberto

2009-01-01

After several years of research and development the Time-Of-Flight detector of ALICE (A Large Ion Collider Experiment) has been constructed and is presently fully installed and operative in the experimental area located at the interaction point n.2 of the LHC (Large Hadron Collider) at CERN. Particle identification in ALICE is essential, as many observables are either mass or flavour dependent, therefore many different techniques are used to cover the largest possible momentum range. As said, the TOF (Time- Of-Flight) detector, of which a comprehensive review is given in Chapter 2, is dedicated to hadron identification at medium momenta. The detector exploits the novel technology based on the Multigap Resistive Plate Chamber (MRPC) which guarantees the excellent performance required for a very large time-of-flight array. The construction of the ALICE TOF detector has required the assembly of a large number of MRPC detectors which has been successfully carried out thanks to a careful mass production controlled...

Characterization of ornidazole metabolites in human bile after intraveneous doses by ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry

Directory of Open Access Journals (Sweden)

Jiangbo Du

2012-04-01

Full Text Available Ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS was used to characterize ornidazole metabolites in human bile after intravenous doses. A liquid chromatography tandem mass spectrometry (LC–MS/MS assay was developed for the determination of the bile level of ornidazole. Bile samples, collected from four patients with T-tube drainage after biliary tract surgery, were prepared by protein precipitation with acetonitrile before analysis. A total of 12 metabolites, including 10 novel metabolites, were detected and characterized. The metabolites of ornidazole in human bile were the products of hydrochloride (HCl elimination, oxidative dechlorination, hydroxylation, sulfation, diastereoisomeric glucuronation, and substitution of NO2 or Cl atom by cysteine or N-acetylcysteine, and oxidative dechlorination followed by further carboxylation. The bile levels of ornidazole at 12 h after multiple intravenous infusions were well above its minimal inhibitory concentration for common strains of anaerobic bacteria.

Accelerated time-of-flight (TOF) PET image reconstruction using TOF bin subsetization and TOF weighting matrix pre-computation

International Nuclear Information System (INIS)

Mehranian, Abolfazl; Kotasidis, Fotis; Zaidi, Habib

2016-01-01

Time-of-flight (TOF) positron emission tomography (PET) technology has recently regained popularity in clinical PET studies for improving image quality and lesion detectability. Using TOF information, the spatial location of annihilation events is confined to a number of image voxels along each line of response, thereby the cross-dependencies of image voxels are reduced, which in turns results in improved signal-to-noise ratio and convergence rate. In this work, we propose a novel approach to further improve the convergence of the expectation maximization (EM)-based TOF PET image reconstruction algorithm through subsetization of emission data over TOF bins as well as azimuthal bins. Given the prevalence of TOF PET, we elaborated the practical and efficient implementation of TOF PET image reconstruction through the pre-computation of TOF weighting coefficients while exploiting the same in-plane and axial symmetries used in pre-computation of geometric system matrix. In the proposed subsetization approach, TOF PET data were partitioned into a number of interleaved TOF subsets, with the aim of reducing the spatial coupling of TOF bins and therefore to improve the convergence of the standard maximum likelihood expectation maximization (MLEM) and ordered subsets EM (OSEM) algorithms. The comparison of on-the-fly and pre-computed TOF projections showed that the pre-computation of the TOF weighting coefficients can considerably reduce the computation time of TOF PET image reconstruction. The convergence rate and bias-variance performance of the proposed TOF subsetization scheme were evaluated using simulated, experimental phantom and clinical studies. Simulations demonstrated that as the number of TOF subsets is increased, the convergence rate of MLEM and OSEM algorithms is improved. It was also found that for the same computation time, the proposed subsetization gives rise to further convergence. The bias-variance analysis of the experimental NEMA phantom and a clinical

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.

A high-resolution time-of-flight spectrometer for fission fragments and ion beams

International Nuclear Information System (INIS)

Kosev, Krasimir Milchev

2007-01-01

For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ( 226 Ra, 222 Rn, 210 Po, 218 Po, 214 Po) α-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a 238 U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)

A high-resolution time-of-flight spectrometer for fission fragments and ion beams

Energy Technology Data Exchange (ETDEWEB)

Kosev, Krasimir Milchev

2007-07-01

For the purpose of fission-fragment detection a double time-of-flight (TOF) spectrometer has been developed. The key component of the TOF spectrometer is a TOF detector consisting of multichannel-plate (MCP) detectors with a position-sensitive readout, a foil for secondary electron (SE) production and an electrostatic mirror. The fission fragments are detected by measuring the SEs impinging on the position-sensitive anode after emission from the foil, acceleration and deflection by the electrostatic mirror. The functionality of the different detector components is proven in detail. Optimised schemes for the high-voltage supplies of the MCP detectors have been implemented successfully. In order to process the multichannel-plate detector signals optimally, a new state-of-the-art constant-fraction discriminator based on the amplitude and rise time compensated technique with very low threshold capabilities and optimised walk properties has been developed and incorporated into the setup. In a setup consisting of two mirror MCP detectors, we could successfully observe the TOF spectrum of a mixed ({sup 226}Ra,{sup 222}Rn,{sup 210}Po,{sup 218}Po,{sup 214}Po) {alpha}-source. Testing photo-fission experiments were performed at the bremsstrahlung facility at the ELBE accelerator. The setup consisted of two mirror detectors (first arm) and a 80 mm diameter MCP detector (second arm) with a {sup 238}U target positioned in between. TOF measurements with two bremsstrahlung end-point energies of 12.9 and 16.0 MeV were carried out. A clear cut separation of the TOF peaks for the medium-mass and heavy fission fragments was observed. (orig.)