Isobaric yield curves at A=72 from the spallation of medium mass isotopes by intermediate energy protons

International Nuclear Information System (INIS)

Tobin, M.J.; Karol, P.J.; Department of Chemistry, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213)

1989-01-01

Cross sections of radionuclides in the A∼72 mass region produced by the interaction 800 MeV protons with 89 Y, /sup 92,96,100/Mo, and 130 Te were measured. Particular emphasis was paid to the measurement of short-lived products far from β stability. The cross sections were used to generate isobaric yield curves at A=72. Precise characterization of these curves showed that the distribution parameters (mean, standard deviation, skewness) vary in a regular fashion with target N/Z. For 89 Y, relative isobaric curves produced by 500 and 800 MeV protons were found to be identical within experimental error. The yield distributions for the /sup 92,96,100/Mo targets also scaled with those from an earlier alpha-induced spallation study. These findings lend strong support to the argument that the spallation mechanism is independent of projectile energy and target composition

Determination of 5-fluorouracil in plasma with HPLC-tandem mass spectrometry

NARCIS (Netherlands)

van Kuilenburg, A. B. P.; van Lenthe, H.; Maring, J. G.; van Gennip, A. H.

2006-01-01

In this article, we describe a fast and specific method to measure 5FU with HPLC tandem-mass spectrometry. Reversed-phase HPLC was combined with electrospray ionization tandem mass spectrometry and detection was performed by multiple-reaction monitoring. Stable-isotope-labeled 5FU (1,3-15N2-5FU) was

Simulation of Two Dimensional Electrophoresis and Tandem Mass Spectrometry for Teaching Proteomics

Science.gov (United States)

Fisher, Amanda; Sekera, Emily; Payne, Jill; Craig, Paul

2012-01-01

In proteomics, complex mixtures of proteins are separated (usually by chromatography or electrophoresis) and identified by mass spectrometry. We have created 2DE Tandem MS, a computer program designed for use in the biochemistry, proteomics, or bioinformatics classroom. It contains two simulations--2D electrophoresis and tandem mass spectrometry.…

Tandem mass spectrometry data quality assessment by self-convolution

Directory of Open Access Journals (Sweden)

Tham Wai

2007-09-01

Full Text Available Abstract Background Many algorithms have been developed for deciphering the tandem mass spectrometry (MS data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. Results The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. Conclusion We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the

Tandem mass spectrometry data quality assessment by self-convolution.

Science.gov (United States)

Choo, Keng Wah; Tham, Wai Mun

2007-09-20

Many algorithms have been developed for deciphering the tandem mass spectrometry (MS) data sets. They can be essentially clustered into two classes. The first performs searches on theoretical mass spectrum database, while the second based itself on de novo sequencing from raw mass spectrometry data. It was noted that the quality of mass spectra affects significantly the protein identification processes in both instances. This prompted the authors to explore ways to measure the quality of MS data sets before subjecting them to the protein identification algorithms, thus allowing for more meaningful searches and increased confidence level of proteins identified. The proposed method measures the qualities of MS data sets based on the symmetric property of b- and y-ion peaks present in a MS spectrum. Self-convolution on MS data and its time-reversal copy was employed. Due to the symmetric nature of b-ions and y-ions peaks, the self-convolution result of a good spectrum would produce a highest mid point intensity peak. To reduce processing time, self-convolution was achieved using Fast Fourier Transform and its inverse transform, followed by the removal of the "DC" (Direct Current) component and the normalisation of the data set. The quality score was defined as the ratio of the intensity at the mid point to the remaining peaks of the convolution result. The method was validated using both theoretical mass spectra, with various permutations, and several real MS data sets. The results were encouraging, revealing a high percentage of positive prediction rates for spectra with good quality scores. We have demonstrated in this work a method for determining the quality of tandem MS data set. By pre-determining the quality of tandem MS data before subjecting them to protein identification algorithms, spurious protein predictions due to poor tandem MS data are avoided, giving scientists greater confidence in the predicted results. We conclude that the algorithm performs well

Analysis of posttranslational modifications of proteins by tandem mass spectrometry

DEFF Research Database (Denmark)

Larsen, Martin Røssel; Trelle, Morten B; Thingholm, Tine E

2006-01-01

-temporal distribution in cells and tissues. Most PTMs can be detected by protein and peptide analysis by mass spectrometry (MS), either as a mass increment or a mass deficit relative to the nascent unmodified protein. Tandem mass spectrometry (MS/MS) provides a series of analytical features that are highly useful...

Matrix interference evaluation employing GC and LC coupled to triple quadrupole tandem mass spectrometry.

Science.gov (United States)

Uclés, S; Lozano, A; Sosa, A; Parrilla Vázquez, P; Valverde, A; Fernández-Alba, A R

2017-11-01

Gas and liquid chromatography coupled to triple quadrupole tandem mass spectrometry are currently the most powerful tools employed for the routine analysis of pesticide residues in food control laboratories. However, whatever the multiresidue extraction method, there will be a residual matrix effect making it difficult to identify/quantify some specific compounds in certain cases. Two main effects stand out: (i) co-elution with isobaric matrix interferents, which can be a major drawback for unequivocal identification, and therefore false negative detections, and (ii) signal suppression/enhancement, commonly called the "matrix effect", which may cause serious problems including inaccurate quantitation, low analyte detectability and increased method uncertainty. The aim of this analytical study is to provide a framework for evaluating the maximum expected errors associated with the matrix effects. The worst-case study contrived to give an estimation of the extreme errors caused by matrix effects when extraction/determination protocols are applied in routine multiresidue analysis. Twenty-five different blank matrices extracted with the four most common extraction methods used in routine analysis (citrate QuEChERS with/without PSA clean-up, ethyl acetate and the Dutch mini-Luke "NL" methods) were evaluated by both GC-QqQ-MS/MS and LC-QqQ-MS/MS. The results showed that the presence of matrix compounds with isobaric transitions to target pesticides was higher in GC than under LC in the experimental conditions tested. In a second study, the number of "potential" false negatives was evaluated. For that, ten matrices with higher percentages of natural interfering components were checked. Additionally, the results showed that for more than 90% of the cases, pesticide quantification was not affected by matrix-matched standard calibration when an interferent was kept constant along the calibration curve. The error in quantification depended on the concentration level. In a

Evaluation of laser diode thermal desorption-tandem mass spectrometry (LDTD-MS-MS) in forensic toxicology.

Science.gov (United States)

Bynum, Nichole D; Moore, Katherine N; Grabenauer, Megan

2014-10-01

Many forensic laboratories experience backlogs due to increased drug-related cases. Laser diode thermal desorption (LDTD) has demonstrated its applicability in other scientific areas by providing data comparable with instrumentation, such as liquid chromatography-tandem mass spectrometry, in less time. LDTD-MS-MS was used to validate 48 compounds in drug-free human urine and blood for screening or quantitative analysis. Carryover, interference, limit of detection, limit of quantitation, matrix effect, linearity, precision and accuracy and stability were evaluated. Quantitative analysis indicated that LDTD-MS-MS produced precise and accurate results with the average overall within-run precision in urine and blood represented by a %CV forensic toxicology but before it can be successfully implemented that there are some challenges that must be addressed. Although the advantages of the LDTD system include minimal maintenance and rapid analysis (∼10 s per sample) which makes it ideal for high-throughput forensic laboratories, a major disadvantage is its inability or difficulty analyzing isomers and isobars due to the lack of chromatography without the use of high-resolution MS; therefore, it would be best implemented as a screening technique. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Differentiation of isomeric N-glycan structures by normal-phase liquid chromatography-MALDI-TOF/TOF tandem mass spectrometry.

Science.gov (United States)

Maslen, Sarah; Sadowski, Pawel; Adam, Alex; Lilley, Kathryn; Stephens, Elaine

2006-12-15

The detailed characterization of protein N-glycosylation is very demanding given the many different glycoforms and structural isomers that can exist on glycoproteins. Here we report a fast and sensitive method for the extensive structure elucidation of reducing-end labeled N-glycan mixtures using a combination of capillary normal-phase HPLC coupled off-line to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and TOF/TOF-MS/MS. Using this method, isobaric N-glycans released from honey bee phospholipase A2 and Arabidopsis thaliana glycoproteins were separated by normal-phase chromatography and subsequently identified by key fragment ions in the MALDI-TOF/TOF tandem mass spectra. In addition, linkage and branching information were provided by abundant cross-ring and "elimination" fragment ions in the MALDI-CID spectra that gave extensive structural information. Furthermore, the fragmentation characteristics of N-glycans reductively aminated with 2-aminobenzoic acid and 2-aminobenzamide were compared. The identification of N-glycans containing 3-linked core fucose was facilitated by distinctive ions present only in the MALDI-CID spectra of 2-aminobenzoic acid-labeled oligosaccharides. To our knowledge, this is the first MS/MS-based technique that allows confident identification of N-glycans containing 3-linked core fucose, which is a major allergenic determinant on insect and plant glycoproteins.

Accelerator Mass Spectrometry at the Nuclear Science Laboratory: Applications to Nuclear Astrophysics

Science.gov (United States)

Collon, P.; Bauder, W.; Bowers, M.; Lu, W.; Ostdiek, K.; Robertson, D.

The Accelerator Mass Spectrometry (AMS) program at the Nuclear Science Laboratory of the University of Notre Dame is focused on measurements related to galactic radioactivity and to nucleosynthesis of main stellar burning as well as the production of so called Short-Lived Radionuclides (SLRs) in the Early Solar System (ESS). The research program is based around the 11MV FN tandem accelerator and the use of the gas-filled magnet technique for isobar separation. Using a technique that evolved from radiocarbon dating, this paper presents a number of research programs that rely on the use of an 11MV tandem accelerator at the center of the AMS program.

Development of an advanced spacecraft tandem mass spectrometer

Science.gov (United States)

Drew, Russell C.

1992-03-01

The purpose of this research was to apply current advanced technology in electronics and materials to the development of a miniaturized Tandem Mass Spectrometer that would have the potential for future development into a package suitable for spacecraft use. The mass spectrometer to be used as a basis for the tandem instrument would be a magnetic sector instrument, of Nier-Johnson configuration, as used on the Viking Mars Lander mission. This instrument configuration would then be matched with a suitable second stage MS to provide the benefits of tandem MS operation for rapid identification of unknown organic compounds. This tandem instrument is configured with a newly designed GC system to aid in separation of complex mixtures prior to MS analysis. A number of important results were achieved in the course of this project. Among them were the development of a miniaturized GC subsystem, with a unique desorber-injector, fully temperature feedback controlled oven with powered cooling for rapid reset to ambient conditions, a unique combination inlet system to the MS that provides for both membrane sampling and direct capillary column sample transfer, a compact and ruggedized alignment configuration for the MS, an improved ion source design for increased sensitivity, and a simple, rugged tandem MS configuration that is particularly adaptable to spacecraft use because of its low power and low vacuum pumping requirements. The potential applications of this research include use in manned spacecraft like the space station as a real-time detection and warning device for the presence of potentially harmful trace contaminants of the spacecraft atmosphere, use as an analytical device for evaluating samples collected on the Moon or a planetary surface, or even use in connection with monitoring potentially hazardous conditions that may exist in terrestrial locations such as launch pads, environmental test chambers or other sensitive areas. Commercial development of the technology

Experimental arguments in favour of 5/2 isospin isobars

International Nuclear Information System (INIS)

Nilov, A.F.; Kaidalov, A.B.; Lomkatsi, G.S.; Smolyankin, V.T.

1978-01-01

Search for baryon resonances with the 5/2 isotopic spin was carried out. Experimental data was obtained in π - p interactions on the hydrogen bubble chamber at 4.5 GeV/c. The investigated channels of the reaction were nπ + π + π - π - , pπ + π - π - π 0 and pπ + π - π - . The effective mass distributions of the products of the reaction were presented. The results of the paper pointed out that 5/2 isobars could be produced in the first channel which corresponded the Feynman diagram with the Δ - (1232) exchange. Particle production of the Δ ++ (1232) isobar in the second and third channels was an inderect evidence in favour

Isobar propagation in the nuclear medium

International Nuclear Information System (INIS)

Moniz, E.J.

1976-01-01

It is argued that introduction of the isobar degree of freedom in describing pion-nucleus interactions provides a convenient, unified framework within which to discuss both many-body corrections to the standard multiple scattering approach and the properties of the Δ(1232) in nuclear matter. Important aspects of isobar-nucleus dynamics, namely, isobar-hole interactions and Δ self-energy modifications, are discussed in the context of pion elastic scattering and incoherent pion production

Authentication of Fish Products by Large-Scale Comparison of Tandem Mass Spectra

DEFF Research Database (Denmark)

Wulff, Tune; Nielsen, Michael Engelbrecht; Deelder, André M.

2013-01-01

Authentication of food is a major concern worldwide to ensure that food products are correctly labeled in terms of which animals are actually processed for consumption. Normally authentication is based on species recognition by comparison of selected sequences of DNA or protein. We here present...... a new robust, proteome-wide tandem mass spectrometry method for species recognition and food product authentication. The method does not use or require any genome sequences or selection of tandem mass spectra but uses all acquired data. The experimental steps were performed in a simple, standardized...

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)

Online characterization of isomeric/isobaric components in the gas phase of mainstream cigarette smoke by tunable synchrotron radiation vacuum ultraviolet photoionization time-of-flight mass spectrometry and photoionization efficiency curve simulation.

Science.gov (United States)

Pan, Yang; Hu, Yonghua; Wang, Jian; Ye, Lili; Liu, Chengyuan; Zhu, Zhixiang

2013-12-17

A newly developed, qualitative and quantitative method based on tunable synchrotron radiation vacuum ultraviolet photoionization time-of-flight mass spectrometry (SR-VUV-PI-TOFMS) and photoionization efficiency (PIE) curve simulation was applied for the online analysis of isomers and isobaric compounds in the gas phase of mainstream cigarette smoke. After blocking the particulate phase components by the Cambridge filter pad, a puff of fresh gas-phase cigarette smoke was immediately introduced into a vacuum ionization chamber through a heated capillary, then was photoionized, and analyzed by a TOF mass spectrometer. The PIE curves for the mass peaks up to m/z = 106 were measured between 8.0 and 10.7 eV. Some components could be directly identified by their discriminated ionization energies (IEs) on the PIE curve. By simulating the PIE curve with the sum of scaled absolute photoionization cross sections (PICSs), complex isomeric/isobaric compounds along with their mole fractions could be obtained when the best-fitting was realized between experimental and simulated PIE curves. A series of reported toxic compounds for quantification, such as 1,3-butadiene (m/z = 54), 1,3-cyclopentadiene (m/z = 66), benzene (m/z = 78), xylene (m/z = 106), 2-propenal (m/z = 56), acetone and propanal (m/z = 58), crotonaldehyde (m/z = 70), furan and isoprene (m/z = 68), were all found to have other isomers and/or isobaric compounds with considerable abundances. Some isomers have never been reported previously in cigarette smoke, like C5H6 isomers 1-penten-3-yne, 3-penten-1-yne, and 1-penten-4-yne at m/z = 66. Isomeric/isobaric compounds characterization for the mass peaks and mole fraction calculations were discussed in detail below 10.7 eV, an energy value covering several conventional used VUV light sources.

Isobar separation of 93Zr and 93Nb at 24 MeV with a new multi-anode ionization chamber

International Nuclear Information System (INIS)

Martschini, Martin; Buchriegler, Josef; Collon, Philippe; Kutschera, Walter; Lachner, Johannes; Lu, Wenting; Priller, Alfred; Steier, Peter; Golser, Robin

2015-01-01

93 Zr with a half-life of 1.6 Ma is produced with high yield in nuclear fission, and thus should be present as a natural or anthropogenic trace isotope in all compartments of the general environment. Sensitive measurements of this isotope would immediately find numerous applications, however, its detection at sufficiently low levels has not yet been achieved. AMS measurements of 93 Zr suffer from the interference of the stable isobar 93 Nb. At the Vienna Environmental Research Accelerator VERA a new multi-anode ionization chamber was built. It is optimized for isobar separation in the medium mass range and is based on the experience from AMS experiments of 36 Cl at our 3-MV tandem accelerator facility. The design provides high flexibility in anode configuration and detector geometry. After validating the excellent energy resolution of the detector with 36 S, it was recently used to study iron–nickel and zirconium–niobium–molybdenum isobar separation. To our surprise, the separation of 94 Zr (Z = 40) from 94 Mo (Z = 42) was found to be much better than that of 58 Fe (Z = 26) from 58 Ni (Z = 28), despite the significantly larger ΔZ/Z of the latter pair. This clearly contradicts results from SRIM-simulations and suggests that differences in the stopping behavior may unexpectedly favor identification of 93 Zr. At 24 MeV particle energy, a 93 Nb (Z = 41) suppression factor of 1000 is expected based on a synthetic 93 Zr spectrum obtained by interpolation between experimental spectra from the two neighboring stable isotopes 92 Zr and 94 Zr. Assuming realistic numbers for chemical niobium reduction, a detection level of 93 Zr/Zr below 10 −9 seems feasible.

Quantitative Proteomics Analysis of Altered Protein Expression in the Placental Villous Tissue of Early Pregnancy Loss Using Isobaric Tandem Mass Tags

Directory of Open Access Journals (Sweden)

Xiaobei Ni

2014-01-01

Full Text Available Many pregnant women suffer miscarriages during early gestation, but the description of these early pregnancy losses (EPL can be somewhat confusing because of the complexities of early development. Thus, the identification of proteins with different expression profiles related to early pregnancy loss is essential for understanding the comprehensive pathophysiological mechanism. In this study, we report a gel-free tandem mass tags- (TMT- labeling based proteomic analysis of five placental villous tissues from patients with early pregnancy loss and five from normal pregnant women. The application of this method resulted in the identification of 3423 proteins and 19647 peptides among the patient group and the matched normal control group. Qualitative and quantitative proteomic analysis revealed 51 proteins to be differentially abundant between the two groups (≥1.2-fold, Student's t-test, P<0.05. To obtain an overview of the biological functions of the proteins whose expression levels altered significantly in EPL group, gene ontology analysis was performed. We also investigated the twelve proteins with a difference over 1.5-fold using pathways analysis. Our results demonstrate that the gel-free TMT-based proteomic approach allows the quantification of differences in protein expression levels, which is useful for obtaining molecular insights into early pregnancy loss.

The MR-TOF-MS isobar separator for the TITAN facility at TRIUMF

Energy Technology Data Exchange (ETDEWEB)

Jesch, Christian; Dickel, Timo, E-mail: t.dickel@gsi.de; Plaß, Wolfgang R. [Justus-Liebig-University (Germany); Short, Devin [Simon Fraser University (Canada); Ayet San Andres, Samuel [Justus-Liebig-University (Germany); Dilling, Jens [TRIUMF (Canada); Geissel, Hans; Greiner, Florian; Lang, Johannes [Justus-Liebig-University (Germany); Leach, Kyle G. [Simon Fraser University (Canada); Lippert, Wayne; Scheidenberger, Christoph [Justus-Liebig-University (Germany); Yavor, Mikhail I. [Institute for Analytical Instrumentation, Russian Academy of Science (Russian Federation)

2015-11-15

At TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN) a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) will extend TITAN’s capabilities and facilitate mass measurements and in-trap decay spectroscopy of exotic nuclei that so far have not been possible due to strong isobaric contamination. This MR-TOF-MS will also enable mass measurements of very short-lived nuclides (half-life > 1 ms) that are produced in very low quantities (a few detected ions overall). In order to allow the installation of an MR-TOF-MS in the restricted space on the platform, on which the TITAN facility is located, novel mass spectrometric methods have been developed. Transport, cooling and distribution of the ions inside the device is done using a buffer gas-filled RFQ-based ion beam switchyard. Mass selection is achieved using a dynamic retrapping technique after time-of-flight analysis in an electrostatic isochronous reflector system. Only due to the combination of these novel methods the realization of an MR-TOF-MS based isobar separator at TITAN has become possible. The device has been built, commissioned off-line and is currently under installation at TITAN.

The MR-TOF-MS isobar separator for the TITAN facility at TRIUMF

Science.gov (United States)

Jesch, Christian; Dickel, Timo; Plaß, Wolfgang R.; Short, Devin; Ayet San Andres, Samuel; Dilling, Jens; Geissel, Hans; Greiner, Florian; Lang, Johannes; Leach, Kyle G.; Lippert, Wayne; Scheidenberger, Christoph; Yavor, Mikhail I.

2015-11-01

At TRIUMF's Ion Trap for Atomic and Nuclear Science (TITAN) a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) will extend TITAN's capabilities and facilitate mass measurements and in-trap decay spectroscopy of exotic nuclei that so far have not been possible due to strong isobaric contamination. This MR-TOF-MS will also enable mass measurements of very short-lived nuclides (half-life > 1 ms) that are produced in very low quantities (a few detected ions overall). In order to allow the installation of an MR-TOF-MS in the restricted space on the platform, on which the TITAN facility is located, novel mass spectrometric methods have been developed. Transport, cooling and distribution of the ions inside the device is done using a buffer gas-filled RFQ-based ion beam switchyard. Mass selection is achieved using a dynamic retrapping technique after time-of-flight analysis in an electrostatic isochronous reflector system. Only due to the combination of these novel methods the realization of an MR-TOF-MS based isobar separator at TITAN has become possible. The device has been built, commissioned off-line and is currently under installation at TITAN.

Accelerator mass spectrometry with a coupled tandem-linac system

International Nuclear Information System (INIS)

Kutschera, W.

1984-01-01

A coupled system provides higher energies, which allows one to extend AMS to hitherto untouched mass regions. Another important argument is that the complexity, although bothersome for the operation, increases the selectivity of detecting a particular isotope. The higher-energy argument holds for any heavy-ion accelerator which is capable of delivering higher energy than a tandem. The present use of tandem-linac combinations for AMS, rather than cyclotrons, linacs or combinations of these machines, has mainly to do with the fact that this technique was almost exclusively developed around tandem accelerators. Therefore the tandem-linac combination is a natural extension to higher energies. The use of negative ions has some particular advantages in suppressing background from unwanted elements that do not form stable negative ions (e.g., N, Mg, Ar). On the other hand, this limits the detection of isotopes to elements which do form negative ions. For particular problems it may therefore be advantageous to use a positive-ion machine. What really matters most for choosing one or the other machine is to what extent the entire accelerator system can be operated in a truly quantiative way from the ion source to the detection system. 20 references, 4 figures

Interpretation of Tandem Mass Spectrometry (MSMS) Spectra for Peptide Analysis

DEFF Research Database (Denmark)

Hjernø, Karin; Højrup, Peter

2015-01-01

The aim of this chapter is to give a short introduction to peptide analysis by mass spectrometry (MS) and interpretation of fragment mass spectra. Through examples and guidelines we demonstrate how to understand and validate search results and how to perform de novo sequencing based on the often...... very complex fragmentation pattern obtained by tandem mass spectrometry (also referred to as MSMS). The focus is on simple rules for interpretation of MSMS spectra of tryptic as well as non-tryptic peptides....

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)

MilQuant: a free, generic software tool for isobaric tagging-based quantitation.

Science.gov (United States)

Zou, Xiao; Zhao, Minzhi; Shen, Hongyan; Zhao, Xuyang; Tong, Yuanpeng; Wang, Qingsong; Wei, Shicheng; Ji, Jianguo

2012-09-18

Isobaric tagging techniques such as iTRAQ and TMT are widely used in quantitative proteomics and especially useful for samples that demand in vitro labeling. Due to diversity in choices of MS acquisition approaches, identification algorithms, and relative abundance deduction strategies, researchers are faced with a plethora of possibilities when it comes to data analysis. However, the lack of generic and flexible software tool often makes it cumbersome for researchers to perform the analysis entirely as desired. In this paper, we present MilQuant, mzXML-based isobaric labeling quantitator, a pipeline of freely available programs that supports native acquisition files produced by all mass spectrometer types and collection approaches currently used in isobaric tagging based MS data collection. Moreover, aside from effective normalization and abundance ratio deduction algorithms, MilQuant exports various intermediate results along each step of the pipeline, making it easy for researchers to customize the analysis. The functionality of MilQuant was demonstrated by four distinct datasets from different laboratories. The compatibility and extendibility of MilQuant makes it a generic and flexible tool that can serve as a full solution to data analysis of isobaric tagging-based quantitation. Copyright © 2012 Elsevier B.V. All rights reserved.

Delta isobars in neutron stars

Directory of Open Access Journals (Sweden)

Pagliara Giuseppe

2015-01-01

Full Text Available The appearance of delta isobars in beta-stable matter is regulated by the behavior of the symmetry energy at densities larger than saturation density. We show that by taking into account recent constraints on the density derivative of the symmetry energy and the theoretical and experimental results on the excitations of delta isobars in nuclei, delta isobars are necessary ingredients for the equations of state used for studying neutron stars. We analyze the effect of the appearance of deltas on the structure of neutron stars: as in the case of hyperons, matter containing delta is too soft for allowing the existence of 2M⊙ neutron stars. Quark stars on the other hand, could reach very massive configurations and they could form from a process of conversion of hadronic stars in which an initial seed of strangeness appears through hyperons.

AMS of 36Cl with the VERA 3 MV tandem accelerator

International Nuclear Information System (INIS)

Martschini, Martin; Andersson, Pontus; Forstner, Oliver; Golser, Robin; Hanstorp, Dag; Lindahl, Anton O.; Kutschera, Walter; Pavetich, Stefan; Priller, Alfred; Rohlén, Johan; Steier, Peter; Suter, Martin; Wallner, Anton

2013-01-01

Recent progress with compact ionization chambers has opened new possibilities for isobar suppression in accelerator mass spectrometry (AMS). Separation of 36 Cl (t 1/2 = 0.30 Ma) at natural isotopic levels from its stable isobar 36 S became feasible at particle energies of 24 MeV, which are also accessible for medium-sized tandem accelerators with 3 MV terminal voltage like VERA (Vienna Environmental Research Accelerator). Investigations with an ionization chamber revealed how physics favors isobar separation even at energies below the maximum of the Bragg curve. The strong energy focusing effect at high energy losses reduces energy straggling significantly and isobar separation steadily increases up to almost full energy loss. With an optimized detection setup, sulfur suppression factors of 2 × 10 4 have been achieved. Refraining from the additional use of degrader foils has the benefit of high transmission to the detector (∼16%), but requires a low sulfur output from the ion source. Therefore several backing materials have been screened for sulfur content. The dependence of the sulfur output on the AgCl sample size has been investigated as well. Precision and accuracy have been thoroughly assessed over the last two years. Since drifts in the spectra are efficiently corrected by monitoring the position of the 36 S peak, the reproducibility for high ratio samples ( 36 Cl/Cl > 10 −12 ) is better than 2%. Our blank value of 36 Cl/Cl ≈ (5 ± 5) × 10 −16 is competitive to other labs. 36 Cl has become a routine AMS-isotope at VERA. Recently we also explored novel techniques for additional sulfur suppression already in the ion source. While results with a small gas reaction cell in front of the sputter target were discouraging, a decrease in the sulfur/chlorine ratio by one order of magnitude was achieved by directing 300 mW continuous wave laser beam at 445 nm towards the cathode in the ion source.

Mass measurements on radioactive isotopes using the ISOLTRAP spectrometer

CERN Document Server

Dilling, J; Kluge, H J; Kohl, A; Lamour, E; Marx, G; Schwarz, S C; Bollen, G; Kellerbauer, A G; Moore, R B; Henry, S

2000-01-01

ISOLTRAP is a Penning trap mass spectrometer installed at the on line isotope separator ISOLDE at CERN. Direct measurements of the masses of short lived radio isotopes are performed using the existing triple trap system. This consists of three electromagnetic traps in tandem: a Paul trap to accumulate and bunch the 60 keV dc beam, a Penning trap for cooling and isobar separation, and a precision Penning trap for the determination of the masses by cyclotron resonance. Measurements of masses of unknown mercury isotopes and in the vicinity of doubly magic /sup 208/Pb are presented, all with an accuracy of delta m/m approximately=1*10/sup -7/. Developments to replace the Paul trap by a radiofrequency quadrupole ion guide system to increase the collection efficiency are presently under way and the status is presented. (10 refs).

Isobaric Quantification of Cerebrospinal Fluid Amyloid-β Peptides in Alzheimer's Disease: C-Terminal Truncation Relates to Early Measures of Neurodegeneration.

Science.gov (United States)

Rogeberg, Magnus; Almdahl, Ina Selseth; Wettergreen, Marianne; Nilsson, Lars N G; Fladby, Tormod

2015-11-06

The amyloid beta (Aβ) peptide is the main constituent of the plaques characteristic of Alzheimer's disease (AD). Measurement of Aβ1-42 in cerebrospinal fluid (CSF) is a valuable marker in AD research, where low levels indicate AD. Although the use of immunoassays measuring Aβ1-38 and Aβ1-40 in addition to Aβ1-42 has increased, quantitative assays of other Aβ peptides remain rarely explored. We recently discovered novel Aβ peptides in CSF using antibodies recognizing the Aβ mid-domain region. Here we have developed a method using both Aβ N-terminal and mid-domain antibodies for immunoprecipitation in combination with isobaric labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for relative quantification of endogenous Aβ peptides in CSF. The developed method was used in a pilot study to produce Aβ peptide profiles from 38 CSF samples. Statistical comparison between CSF samples from 19 AD patients and 19 cognitively healthy controls revealed no significant differences at group level. A significant correlation was found between several larger C-terminally truncated Aβ peptides and protein biomarkers for neuronal damage, particularly prominent in the control group. Comparison of the isobaric quantification with immunoassays measuring Aβ1-38 or Aβ1-40 showed good correlation (r(2) = 0.84 and 0.85, respectively) between the two analysis methods. The developed method could be used to assess disease-modifying therapies directed at Aβ production or degradation.

Liquid chromatographic-tandem mass spectrometric determination of selected sulphonamides in milk

NARCIS (Netherlands)

Rhijn, van J.A.; Lasaroms, J.J.P.; Berendsen, B.J.A.; Brinkman, U.A.Th.

2002-01-01

Liquid chromatography–tandem mass spectrometry is used for the quantitative analysis of selected sulphonamides in milk. Ultrafiltration is the only sample pre-treatment technique which is required. Consequently, sample throughput is much higher than with conventional procedures, and analyte

Generalized isobaric multiplet mass equation and its application to the Nolen-Schiffer anomaly

Science.gov (United States)

Dong, J. M.; Zhang, Y. H.; Zuo, W.; Gu, J. Z.; Wang, L. J.; Sun, Y.

2018-02-01

The Wigner isobaric multiplet mass equation (IMME) is the most fundamental prediction in nuclear physics with the concept of isospin. However, it was deduced based on the Wigner-Eckart theorem with the assumption that all charge-violating interactions can be written as tensors of rank two. In the present work, the charge-symmetry breaking (CSB) and charge-independent breaking (CIB) components of the nucleon-nucleon force, which contribute to the effective interaction in nuclear medium, are established in the framework of Brueckner theory with AV18 and AV14 bare interactions. Because such charge-violating components can no longer be expressed as an irreducible tensor due to density dependence, its matrix element cannot be analytically reduced by the Wigner-Eckart theorem. With an alternative approach, we derive a generalized IMME (GIMME) that modifies the coefficients of the original IMME. As the first application of GIMME, we study the long-standing question of the origin of the Nolen-Schiffer anomaly (NSA) found in the Coulomb displacement energy of mirror nuclei. We find that the naturally emerged CSB term in GIMME is largely responsible for explaining the NSA.

Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry

DEFF Research Database (Denmark)

Bornø, Andreas; Foged, Lene; van Hall, Gerrit

2014-01-01

The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose...

Isobar degrees of freedom in nuclei

International Nuclear Information System (INIS)

Muether, H.

1979-01-01

A report is given on some recent investigations of the influence of isobar degrees of freedom on the ground state properties of finite nuclei like e.g. 16 O. The nucleon-nucleon (NN) interaction is constructed in the freamework of an extended one-boson-exchange (OBE) model using non-covariant, time-dependent perturbation theory. The explicit consideration of fourth-order iterative diagrams involving NΔ and ΔΔ intermediate states gives an effective NN interaction in the nuclear many-body system which is less attractive than those which are obtained treating these terms phenomenologically. Therefore the binding energy calculated in the Brueckner-Hartree-Fock approximation is smaller if these effects of isobar degrees of freedom are taken into account. This repulsive effect of isobar configurations is partly counterbalanced by the attraction obtained for three-nucleon terms with intermediate NNΔ states. (Auth.)

Quantitative Thin-Layer Chromatography/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

Energy Technology Data Exchange (ETDEWEB)

Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

2005-01-01

Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

Derivatization reagents in liquid chromatography/electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Santa, Tomofumi

2011-01-01

Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) is one of the most prominent analytical techniques owing to its inherent selectivity and sensitivity. In LC/ESI-MS/MS, chemical derivatization is often used to enhance the detection sensitivity. Derivatization improves the chromatographic separation, and enhances the mass spectrometric ionization efficiency and MS/MS detectability. In this review, an overview of the derivatization reagents which have been applied to LC/ESI-MS/MS is presented, focusing on the applications to low molecular weight compounds. 2010 John Wiley & Sons, Ltd.

Four-nucleon system with Δ-isobar excitation

International Nuclear Information System (INIS)

Deltuva, A.; Fonseca, A.C.; Sauer, P.U.

2008-01-01

The four-nucleon bound state and scattering below three-body breakup threshold are described based on the realistic coupled-channel potential CD Bonn+Δ which allows the excitation of a single nucleon to a Δ isobar. The Coulomb repulsion between protons is included. In the four-nucleon system the two-baryon coupled-channel potential yields effective two-, three- and four-nucleon forces, mediated by the Δ isobar and consistent with each other and with the underlying two-nucleon force. The effect of the four-nucleon force on the studied observables is much smaller than the effect of the three-nucleon force. The inclusion of the Δ isobar is unable to resolve the existing discrepancies with the experimental data

Quantitative Caffeine Analysis Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

Energy Technology Data Exchange (ETDEWEB)

Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

2005-01-01

Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

Multifactorial Understanding of Ion Abundance in Tandem Mass Spectrometry Experiments.

Science.gov (United States)

Fazal, Zeeshan; Southey, Bruce R; Sweedler, Jonathan V; Rodriguez-Zas, Sandra L

2013-01-29

In a bottom-up shotgun approach, the proteins of a mixture are enzymatically digested, separated, and analyzed via tandem mass spectrometry. The mass spectra relating fragment ion intensities (abundance) to the mass-to-charge are used to deduce the amino acid sequence and identify the peptides and proteins. The variables that influence intensity were characterized using a multi-factorial mixed-effects model, a ten-fold cross-validation, and stepwise feature selection on 6,352,528 fragment ions from 61,543 peptide ions. Intensity was higher in fragment ions that did not have neutral mass loss relative to any mass loss or that had a +1 charge state. Peptide ions classified for proton mobility as non-mobile had lowest intensity of all mobility levels. Higher basic residue (arginine, lysine or histidine) counts in the peptide ion and low counts in the fragment ion were associated with lower fragment ion intensities. Higher counts of proline in peptide and fragment ions were associated with lower intensities. These results are consistent with the mobile proton theory. Opposite trends between peptide and fragment ion counts and intensity may be due to the different impact of factor under consideration at different stages of the MS/MS experiment or to the different distribution of observations across peptide and fragment ion levels. Presence of basic residues at all three positions next to the fragmentation site was associated with lower fragment ion intensity. The presence of proline proximal to the fragmentation site enhanced fragmentation and had the opposite trend when located distant from the site. A positive association between fragment ion intensity and presence of sulfur residues (cysteine and methionine) on the vicinity of the fragmentation site was identified. These results highlight the multi-factorial nature of fragment ion intensity and could improve the algorithms for peptide identification and the simulation in tandem mass spectrometry experiments.

Atmospheric pressure ionization-tandem mass spectrometry of the phenicol drug family.

Science.gov (United States)

Alechaga, Élida; Moyano, Encarnación; Galceran, M Teresa

2013-11-01

In this work, the mass spectrometry behaviour of the veterinary drug family of phenicols, including chloramphenicol (CAP) and its related compounds thiamphenicol (TAP), florfenicol (FF) and FF amine (FFA), was studied. Several atmospheric pressure ionization sources, electrospray (ESI), atmospheric pressure chemical ionization and atmospheric pressure photoionization were compared. In all atmospheric pressure ionization sources, CAP, TAP and FF were ionized in both positive and negative modes; while for the metabolite FFA, only positive ionization was possible. In general, in positive mode, [M + H](+) dominated the mass spectrum for FFA, while the other compounds, CAP, TAP and FF, with lower proton affinity showed intense adducts with species present in the mobile phase. In negative mode, ESI and atmospheric pressure photoionization showed the deprotonated molecule [M-H](-), while atmospheric pressure chemical ionization provided the radical molecular ion by electron capture. All these ions were characterized by tandem mass spectrometry using the combined information obtained by multistage mass spectrometry and high-resolution mass spectrometry in a quadrupole-Orbitrap instrument. In general, the fragmentation occurred via cyclization and losses or fragmentation of the N-(alkyl)acetamide group, and common fragmentation pathways were established for this family of compounds. A new chemical structure for the product ion at m/z 257 for CAP, on the basis of the MS(3) and MS(4) spectra is proposed. Thermally assisted ESI and selected reaction monitoring are proposed for the determination of these compounds by ultra high-performance liquid chromatography coupled to tandem mass spectrometry, achieving instrumental detection limits down to 0.1 pg. Copyright © 2013 John Wiley & Sons, Ltd.

A fragmentation study of kaempferol using electrospray quadrupole time-of-flight mass spectrometry at high mass resolution

Science.gov (United States)

March, Raymond E.; Miao, Xiu-Sheng

2004-02-01

A mass spectrometric method based on the combined use of electrospray ionization, collision-induced dissociation and tandem mass spectrometry at high mass resolution has been applied to an investigation of the structural characterization of protonated and deprotonated kaempferol (3,5,7,4'-tetrahydroxyflavone). Low-energy product ion mass spectra of [M+H]+ ions showed simple fragmentations of the C ring that permitted characterization of the substituents in the A and B rings. In addition, four rearrangement reactions accompanied by losses of C2H2O, CHO[radical sign], CO, and H2O were observed. Low-energy product ion mass spectra of [M-H]- ions showed only four rearrangement reactions accompanied by losses of OH[radical sign], CO, CH2O, and C2H2O. The use of elevated cone voltages permitted observation of product ion mass spectra of selected primary and secondary fragment ions so that each fragment ion reported was observed as a direct product of its immediate precursor ion. Product ion mass spectra examined at high mass resolution allowed unambiguous determination of the elemental composition of fragment ions and resolution of two pairs of isobars. Fragmentation mechanisms and ion structures have been proposed.

Isobar configurations in nuclei and short range correlations

CERN Document Server

Weber, H J

1979-01-01

Recent results on short range correlations and isobar configurations are reviewed, and in particular a unitary version of the isobar model, coupling constants and rho -meson transition potentials, a comparison with experiments, the CERN N*-knockout from /sup 4/He, QCD and the NN interaction of short range. (42 refs).

Three-body unitarity with isobars revisited

Energy Technology Data Exchange (ETDEWEB)

Mai, M.; Hu, B. [The George Washington University, Washington, DC (United States); Doering, M. [The George Washington University, Washington, DC (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Pilloni, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Szczepaniak, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Indiana University, Center for Exploration of Energy and Matter, Bloomington, IN (United States); Indiana University, Physics Department, Bloomington, IN (United States)

2017-09-15

The particle exchange model of hadron interactions can be used to describe three-body scattering under the isobar assumption. In this study we start from the 3 → 3 scattering amplitude for spinless particles, which contains an isobar-spectator scattering amplitude. Using a Bethe-Salpeter Ansatz for the latter, we derive a relativistic three-dimensional scattering equation that manifestly fulfills three-body unitarity and two-body unitarity for the sub-amplitudes. This property holds for energies above breakup and also in the presence of resonances in the sub-amplitudes. (orig.)

Matrix effect on the determination of synthetic corticosteroids and diuretics by liquid chromatography-tandem mass spectrometry

Science.gov (United States)

Dikunets, M. A.; Appolonova, S. A.; Rodchenkov, G. M.

2009-04-01

This work presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) procedure for selective and reliable screening of corticosteroids and diuretics in human urine. Sample preparation included the extraction, evaporation of the organic extract under nitrogen, and solution of the dry residue. The extract was analyzed by HPLC combined with tandem mass spectrometry using electro-spraying ionization at atmospheric pressure with negative ion recording. The mass spectra of all compounds were recorded, and the characteristic ions, retention times, and detection limits were determined. The procedure was validated by evaluating the degree of the matrix suppression of ionization, extraction of analytes from human biological liquid, and the selectivity and specificity of determination.

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

Strategies for dereplication of natural compounds using high-resolution tandem mass spectrometry.

Science.gov (United States)

Kind, Tobias; Fiehn, Oliver

2017-09-01

Complete structural elucidation of natural products is commonly performed by nuclear magnetic resonance spectroscopy (NMR), but annotating compounds to most likely structures using high-resolution tandem mass spectrometry is a faster and feasible first step. The CASMI contest 2016 (Critical Assessment of Small Molecule Identification) provided spectra of eighteen compounds for the best manual structure identification in the natural products category. High resolution precursor and tandem mass spectra (MS/MS) were available to characterize the compounds. We used the Seven Golden Rules, Sirius2 and MS-FINDER software for determination of molecular formulas, and then we queried the formulas in different natural product databases including DNP, UNPD, ChemSpider and REAXYS to obtain molecular structures. We used different in-silico fragmentation tools including CFM-ID, CSI:FingerID and MS-FINDER to rank these compounds. Additional neutral losses and product ion peaks were manually investigated. This manual and time consuming approach allowed for the correct dereplication of thirteen of the eighteen natural products.

Determination of 4-Methylimidazole in Ammonia Caramel Using Gas Chromatography–Tandem Mass Spectrometry (GC-MS/MS

Directory of Open Access Journals (Sweden)

Martyna N. Wieczorek

2018-01-01

Full Text Available One of Maillard reaction products formed in the production of ammonia caramel is 4(5-methylimidazole (4-MeI classified as carcinogen. A method of 4-MeI determination based on ion-pair extraction and derivatisation with isobutyl chloroformate with subsequent gas chromatography-tandem mass spectrometry analysis was proposed. Tandem mass spectrometry was applied to reduce the influence of matrix and increase the selectivity and sensitivity of the method. Triple quadrupole GC-MS system was used for this study. The collision energies were optimized for MRM mode. The detection (LOD and quantification limits (LOQ of the elaborated method were 17 and 37.8 μg kg−1, respectively, repeatability was <15% RSD for analyzed caramel samples, and the recovery for 4-MeI was 101%. Comparison of MS/MS with SIM detection on the same instrument proved almost 30 times lower LODs achieved by tandem mass spectrometry compared to SIM. Described method can be routinely used for monitoring 4-MeI as a quality and safety marker in the production of ammonia caramel.

Symmetry energy II: Isobaric analog states

Science.gov (United States)

Danielewicz, Pawel; Lee, Jenny

2014-02-01

Using excitation energies to isobaric analog states (IAS) and charge invariance, we extract nuclear symmetry coefficients, representing a mass formula, on a nucleus-by-nucleus basis. Consistently with charge invariance, the coefficients vary weakly across an isobaric chain. However, they change strongly with nuclear mass and range from aa˜10 MeV at mass A˜10 to aa˜22 MeV at A˜240. Variation with mass can be understood in terms of dependence of nuclear symmetry energy on density and the rise in importance of low densities within nuclear surface in smaller systems. At A≳30, the dependence of coefficients on mass can be well described in terms of a macroscopic volume-surface competition formula with aaV≃33.2 MeV and aaS≃10.7 MeV. Our further investigation shows, though, that the fitted surface symmetry coefficient likely significantly underestimates that for the limit of half-infinite matter. Following the considerations of a Hohenberg-Kohn functional for nuclear systems, we determine how to find in practice the symmetry coefficient using neutron and proton densities, even when those densities are simultaneously affected by significant symmetry-energy and Coulomb effects. These results facilitate extracting the symmetry coefficients from Skyrme-Hartree-Fock (SHF) calculations, that we carry out using a variety of Skyrme parametrizations in the literature. For the parametrizations, we catalog novel short-wavelength instabilities. In our further analysis, we retain only those parametrizations which yield systems that are adequately stable both in the long- and short-wavelength limits. In comparing the SHF and IAS results for the symmetry coefficients, we arrive at narrow (±2.4 MeV) constraints on the symmetry-energy values S(ρ) at 0.04≲ρ≲0.13 fm. Towards normal density the constraints significantly widen, but the normal value of energy aaV and the slope parameter L are found to be strongly correlated. To narrow the constraints, we reach for the

Determination of phospholipid regiochemistry by Ag(I) adduction and tandem mass spectrometry.

Science.gov (United States)

Yoo, Hyun Ju; Håkansson, Kristina

2011-02-15

Collision-activated dissociation (CAD) and infrared multiphoton dissociation (IRMPD) of Ag-adducted phospholipids were investigated as structural tools. Previously, determination of the acyl chains at the two phospholipid esterification sites has been performed based on the R(1)COO(-)/R(2)COO(-) ratio in negative ion mode CAD tandem mass spectrometry. However, the observed product ion ratio is dependent on the extent of unsaturation of the fatty acyl group at sn-2 as well as on the total chain length. Similarly, in positive ion mode CAD with/without alkaline or alkaline earth metal adduction, the ratio of product ions resulting from either R(1)COOH or R(2)COOH neutral losses is dependent on the nature of the phospholipid polar headgroup. Ag(+) ion chromatography, in which silver ions are part of the stationary phase, can provide information on double bond number/distribution as well as double bond configuration (cis/trans) because of interaction between Ag(+) ions and olefinic π electrons of fatty acids and lipids. We hypothesized that interactions between double bonds and Ag(+) may be utilized to also reveal phospholipid esterification site information in tandem mass spectrometry. CAD and IRMPD of Ag-adducted phospholipids with unsaturated fatty acids (R(x)COOH, x = 1 or 2) provided characteristic product ions, [R(x)COOH + Ag](+), and their neutral losses. The characteristic product ions and their abundances do not depend on the type of polar headgroup or the number of double bonds of unsaturated acyl chains. Tandem mass spectrometry of Cu-adducted phospholipids was also performed for comparison based on the Lewis acid and base properties of Cu(+) and phospholipid double bonds, respectively.

Tandem Mass Spectrum Sequencing: An Alternative to Database Search Engines in Shotgun Proteomics.

Science.gov (United States)

Muth, Thilo; Rapp, Erdmann; Berven, Frode S; Barsnes, Harald; Vaudel, Marc

2016-01-01

Protein identification via database searches has become the gold standard in mass spectrometry based shotgun proteomics. However, as the quality of tandem mass spectra improves, direct mass spectrum sequencing gains interest as a database-independent alternative. In this chapter, the general principle of this so-called de novo sequencing is introduced along with pitfalls and challenges of the technique. The main tools available are presented with a focus on user friendly open source software which can be directly applied in everyday proteomic workflows.

Fast quantitative detection of cocaine in beverages using nanoextractive electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Hu, Bin; Peng, Xuejiao; Yang, Shuiping; Gu, Haiwei; Chen, Huanwen; Huan, Yanfu; Zhang, Tingting; Qiao, Xiaolin

2010-02-01

Without any sample pretreatment, effervescent beverage fluids were manually sprayed into the primary ion plume created by using a nanoelectrospray ionization source for direct ionization, and the analyte ions of interest were guided into an ion trap mass spectrometer for tandem mass analysis. Functional ingredients (e.g., vitamins, taurine, and caffeine, etc.) and spiked impurity (e.g., cocaine) in various beverages, such as Red Bull energy drink, Coco-cola, and Pepsi samples were rapidly identified within 1.5 s. The limit of detection was found to be 7-15 fg (S/N = 3) for cocaine in different samples using the characteristic fragment (m/z 150) observed in the MS(3) experiments. Typical relative standard deviation and recovery of this method were 6.9%-8.6% and 104%-108% for direct analysis of three actual samples, showing that nanoextractive electrospray ionization tandem mass spectrometry is a useful technique for fast screening cocaine presence in beverages. 2010. Published by Elsevier Inc.

Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil

Directory of Open Access Journals (Sweden)

Madelen A. Olofsson

2016-01-01

Full Text Available This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC, and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0 and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The m/z transitions of 180 → 72 and 180 → 84 were applied for the detection of glucosamine and galactosamine and that of 252 → 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method.

Identifying the related compounds using electrospray ionization tandem mass spectrometry: bromotyrosine alkaloids from marine sponge Psammaplysilla purpurea

Digital Repository Service at National Institute of Oceanography (India)

Tilvi, S.; DeSouza, L.

electrospray ionization tandem mass spectrometry (ESI-MS/MS). This sponge has tremendous chemical diversity of bromotyrosine alkaloids. Here we have used the proteomics approach in identifying related bromotyrosine alkaloids based on the predicated mass...

Tandem mass spectrometric analysis of cyclophosphamide, ifosfamide and their metabolites.

Science.gov (United States)

Liu, Zhongfa; Chan, Kenneth K; Wang, Jeffrey J

2005-01-01

A detailed multi-stage (MSn) fragmentation study of cyclophosphamide (CP), ifosfamide (IF) and their major metabolites, using an ion-trap mass spectrometer and a Q-TOF mass spectrometer, was performed with the aid of specifically deuterium-labeled analogs. The analytes showed good responses in positive-ion electrospray mass spectrometry as [MH]+ ions. Tandem mass spectra revealed a wealth of structurally specific ions, allowing characterization of the fragmentation pathways of these analytes. The major fragmentation pathways of the protonated CP and IF are elimination of ethylene from C5 and C6 of 1,3,2-oxazaphosphorine-2-oxide via a McLafferty rearrangement, and cleavage of the P-N bond. However, their activated 4-OOH and 4-OH metabolites primarily underwent hydrogen peroxide elimination and dehydration, respectively, followed by fragmentation pathways similar to those of CP and IF. These results should prove useful in structural elucidation of future analogs of CP and IF, and/or of their metabolites. Copyright (c) 2005 John Wiley & Sons, Ltd.

Fast atom bombardment tandem mass spectrometry of carotenoids

Energy Technology Data Exchange (ETDEWEB)

van Breeman, R.B. [Univ. of Illinois, Chicago, IL (United States); Schmitz, H.H.; Schwartz, S.J. [North Carolina State Univ., Raleigh, NC (United States)

1995-02-01

Positive ion fast atom bombardment (FAB) tandem mass spectrometry (MS-MS) using a double-focusing mass spectrometer with linked scanning at constant B/E and high-energy collisionally activated dissociation (CAD) was used to differentiate 17 different cartenoids, including {beta}-apo-8{prime}- carotenal, astaxanthin, {alpha}-carotene, {beta}-carotene, {gamma}-carotene, {zeta}-carotene, canthaxanthin, {beta}-cryptoxanthin, isozeaxanthin bis (pelargonate), neoxanthin, neurosporene, nonaprene, lutein, lycopene, phytoene, phytofluene, and zeaxanthin. The carotenoids were either synthetic or isolated from plant tissues. The use of FAB ionization minimized degradation or rearrangement of the carotenoid structures due to the inherent thermal instability generally ascribed to these compounds. Instead of protonated molecules, both polar xanthophylls and nonpolar carotenes formed molecular ions, M{sup {center_dot}+}, during FAB ionization. Following collisionally activated dissociation, fragment ions of selected molecular ion precursors showed structural features indicative of the presence of hydroxyl groups, ring systems, ester groups, and aldehyde groups and the extent of aliphatic polyene conjugation. The fragmentation patterns observed in the mass spectra herein may be used as a reference for the structural determination of carotenoids isolated from plant and animal tissues. 18 refs., 4 figs.

Dalitz plot analysis of the $D^+ \\rightarrow K^- K^+ K^+$ decay with the isobar model

CERN Document Server

The LHCb Collaboration

2016-01-01

This note presents a study of the $K^-K^+$ S-wave amplitude in doubly Cabibbo-suppressed ${D^+ \\rightarrow K^- K^+ K^+}$ decays performed using $2 \\text{fb}^{-1}$ of data collected by the LHCb detector in $pp$ collisions at $8~\\text{TeV}$ centre-of-mass energy. The Dalitz plot is studied under the assumption of the isobar model for resonance scattering. Models with combinations of resonant states are tested. Fits of comparable quality are obtained for different $K^-K^+$ S-wave parameterizations. The results obtained indicate that a variation of the S-wave phase at both ends of $K^-K^+$ spectrum is needed to describe the data. Further studies beyond the näive isobar model are foreseen to understand the $K^-K^+$ S-wave.

Biomarker discovery in low-grade breast cancer using isobaric stable isotope tags and two-dimensional liquid chromatography-tandem mass spectrometry (iTRAQ-2DLC-MS/MS) based quantitative proteomic analysis.

Science.gov (United States)

Bouchal, Pavel; Roumeliotis, Theodoros; Hrstka, Roman; Nenutil, Rudolf; Vojtesek, Borivoj; Garbis, Spiros D

2009-01-01

The present pilot study constitutes a proof-of-principle in the use of a quantitative LC-MS/MS based proteomic method for the comparative analysis of representative low-grade breast primary tumor tissues with and without metastases and metastasis in lymph node relative to the nonmetastatic tumor type. The study method incorporated iTRAQ stable isotope labeling, two-dimensional liquid chromatography, nanoelectrospray ionization and high resolution tandem mass spectrometry using the hybrid QqTOF platform (iTRAQ-2DLC-MS/MS). The principal aims of this study were (1) to define the protein spectrum obtainable using this approach, and (2) to highlight potential candidates for verification and validation studies focused on biomarkers involved in metastatic processes in breast cancer. The study resulted in the reproducible identification of 605 nonredundant proteins (p biomarker discovery program.

Tandem Mass Spectrometry for Structural Identification of Sesquiterpene Alkaloids from the Stems of Dendrobium nobile Using LC-QToF.

Science.gov (United States)

Wang, Yan-Hong; Avula, Bharathi; Abe, Naohito; Wei, Feng; Wang, Mei; Ma, Shuang-Cheng; Ali, Zulfiqar; Elsohly, Mahmoud A; Khan, Ikhlas A

2016-05-01

Dendrobium nobile is one of the fundamental herbs in traditional Chinese medicine. Sesquiterpene alkaloids are the main active components in this plant. Due to weak ultraviolet absorption and low content in D. nobile, these sesquiterpene alkaloids have not been extensively studied using chromatographic methods. Herein, tandem mass spectrometry combined with liquid chromatography separation provides a tool for the identification and characterization of the alkaloids from D. nobile. A total of nine sesquiterpene alkaloids were characterized by ultrahigh-performance liquid chromatography tandem mass spectrometry. These alkaloids can be classified into two subgroups that are represented by dendrobine and nobilonine. Tandem mass spectrometric studies revealed the fragmentation pathways of these two subgroup alkaloids that were used for the identification and characterization of other alkaloids in D. nobile. Characterization of these alkaloids using accurate mass and diagnostic fragments provided a reliable methodology for the analysis of D. nobile by ultrahigh-performance liquid chromatography tandem mass spectrometry. The limit of detection was defined as the signal-to-noise ratio equal to 3 : 1. Limits of detection of dendrobine and nobilonine were less than 30 ng/mL. The developed method was applied for the analysis of various Dendrobium species and related dietary supplements. Alkaloids were identified from D. nobile, but not detected from commercial samples including 13 other Dendrobium species and the 7 dietary supplements. Georg Thieme Verlag KG Stuttgart · New York.

Applications of Tandem Mass Spectrometry in the Structure Determination of Permethylated Sialic Acid-containing Oligosaccharides

International Nuclear Information System (INIS)

Yoo, Eun Sun; Yoon, In Mo

2005-01-01

Sets of sialic acid-containing trisaccharides having different internal and terminal linkages have been synthesized to develop a sensitive method for analysis of the reducing terminal linkage positions. The trisaccharides, sialyl(α 2-3)Gal(β 1-3)GalNAc and sialyl(α 2-3)Gal(β 1-X)GlcNAc where X=3, 4 and 6, were synthesized and examined using electrospray ionization (ESI)-collision induced dissociation (CID) tandem mass spectrometry (MS/MS). The compounds chosen for this study are related to terminal groups likely to be found on polylactosamine-like glycoproteins and glycolipids which occur on the surface of mammalian cells. The purpose of this study is to develop tandem mass spectrometral methods to determine detailed carbohydrate structures on permethylated or partially methylated oligosaccharides for future applications on biologically active glycoconjugates and to exploit a faster method of synthesizing a series of structural isomeric oligosaccharides to be used for further mass spectrometry and instrumental analysis

MS2Analyzer: A Software for Small Molecule Substructure Annotations from Accurate Tandem Mass Spectra

Science.gov (United States)

2015-01-01

Systematic analysis and interpretation of the large number of tandem mass spectra (MS/MS) obtained in metabolomics experiments is a bottleneck in discovery-driven research. MS/MS mass spectral libraries are small compared to all known small molecule structures and are often not freely available. MS2Analyzer was therefore developed to enable user-defined searches of thousands of spectra for mass spectral features such as neutral losses, m/z differences, and product and precursor ions from MS/MS spectra in MSP/MGF files. The software is freely available at http://fiehnlab.ucdavis.edu/projects/MS2Analyzer/. As the reference query set, 147 literature-reported neutral losses and their corresponding substructures were collected. This set was tested for accuracy of linking neutral loss analysis to substructure annotations using 19 329 accurate mass tandem mass spectra of structurally known compounds from the NIST11 MS/MS library. Validation studies showed that 92.1 ± 6.4% of 13 typical neutral losses such as acetylations, cysteine conjugates, or glycosylations are correct annotating the associated substructures, while the absence of mass spectra features does not necessarily imply the absence of such substructures. Use of this tool has been successfully demonstrated for complex lipids in microalgae. PMID:25263576

Quantitative profiling of serum samples using TMT protein labelling, fractionation and LC-MS/MS.

Science.gov (United States)

Sinclair, John; Timms, John F

2011-08-01

Blood-borne biomarkers are urgently required for the early detection, accurate diagnosis and prognosis of disease. Additionally, improved methods of profiling serum and plasma proteins for biomarker discovery efforts are needed. Herein, we report a quantitative method based on amino-group labelling of serum proteins (rather than peptides) with isobaric tandem mass tags (TMT) and incorporating immune-based depletion, gel-based and strong anion exchange separation of proteins prior to differential endoproteinase treatment and liquid chromatography tandem mass spectrometry. We report a generally higher level of quantitative coverage of the serum proteome compared to other peptide-based isobaric tagging approaches and show the potential of the method by applying it to a set of unique samples that pre-date the diagnosis of pancreatic cancer. Copyright © 2011 Elsevier Inc. All rights reserved.

Instruction manual for ORNL tandem high abundance sensitivity mass spectrometer

International Nuclear Information System (INIS)

Smith, D.H.; McKown, H.S.; Chrisite, W.H.; Walker, R.L.; Carter, J.A.

1976-06-01

This manual describes the physical characteristics of the tandem mass spectrometer built by Oak Ridge National Laboratory for the International Atomic Energy Agency. Specific requirements met include ability to run small samples, high abundance sensitivity, good precision and accuracy, and adequate sample throughput. The instrument is capable of running uranium samples as small as 10 -12 g and has an abundance sensitivity in excess of 10 6 . Precision and accuracy are enhanced by a special sweep control circuit. Sample throughput is 6 to 12 samples per day. Operating instructions are also given

PepArML: A Meta-Search Peptide Identification Platform for Tandem Mass Spectra.

Science.gov (United States)

Edwards, Nathan J

2013-12-01

The PepArML meta-search peptide identification platform for tandem mass spectra provides a unified search interface to seven search engines; a robust cluster, grid, and cloud computing scheduler for large-scale searches; and an unsupervised, model-free, machine-learning-based result combiner, which selects the best peptide identification for each spectrum, estimates false-discovery rates, and outputs pepXML format identifications. The meta-search platform supports Mascot; Tandem with native, k-score and s-score scoring; OMSSA; MyriMatch; and InsPecT with MS-GF spectral probability scores—reformatting spectral data and constructing search configurations for each search engine on the fly. The combiner selects the best peptide identification for each spectrum based on search engine results and features that model enzymatic digestion, retention time, precursor isotope clusters, mass accuracy, and proteotypic peptide properties, requiring no prior knowledge of feature utility or weighting. The PepArML meta-search peptide identification platform often identifies two to three times more spectra than individual search engines at 10% FDR.

Screening newborns for metabolic disorders based on targeted metabolomics using tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Hye-Ran Yoon

2015-09-01

Full Text Available The main purpose of newborn screening is to diagnose genetic, metabolic, and other inherited disorders, at their earliest to start treatment before the clinical manifestations become evident. Understanding and tracing the biochemical data obtained from tandem mass spectrometry is vital for early diagnosis of metabolic diseases associated with such disorders. Accordingly, it is important to focus on the entire diagnostic process, including differential and confirmatory diagnostic options, and the major factors that influence the results of biochemical analysis. Compared to regular biochemical testing, this is a complex process carried out by a medical physician specialist. It is comprised of an integrated program requiring multidisciplinary approach such as, pediatric specialist, expert scientist, clinical laboratory technician, and nutritionist. Tandem mass spectrometry is a powerful tool to improve screening of newborns for diverse metabolic diseases. It is likely to be used to analyze other treatable disorders or significantly improve existing newborn tests to allow broad scale and precise testing. This new era of various screening programs, new treatments, and the availability of detection technology will prove to be beneficial for the future generations.

Novel product ions of 2-aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi-stage tandem mass spectrometry.

Science.gov (United States)

Johnson, Byron S; Burinsky, David J; Burova, Svetlana A; Davis, Roman; Fitzgerald, Russ N; Matsuoka, Richard T

2012-05-15

The 2-aminoaniline scaffold is of significant value to the pharmaceutical industry and is embedded in a number of pharmacophores including 2-aminoanilides and benzimidazoles. A novel application of coordination ion spray mass spectrometry (CIS-MS) for interrogating the silver ion (Ag(+)) complexes of a homologous series of these compounds using multi-stage tandem mass spectrometry is described. Unlike the ubiquitous alkali metal ion complexes, Ag(+) complexes of 2-aminoanilides and benzimidazoles were found to yield [M - H](+) ions in significant abundance via gas-phase elimination of the metal hydride (AgH) resulting in unique product ion cascades. Sample introduction was by liquid chromatography with mass spectrometry analysis performed on a hybrid linear ion trap/orbitrap instrument capable of high-resolution measurements. Rigorous structural characterization by multi-stage tandem mass spectrometry using [M +  H](+), [M - H](-) and [M - H](+) precursor ions derived from ESI and CIS experiments was performed for the homologous series of 2-aminoanilide and benzimidazole compounds. A full tabular comparison of structural information resulting from these product ion cascades was produced. Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M  +  H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH. Copyright © 2012 John Wiley & Sons, Ltd.

Chemical modification of DNA: Molecular specificity studied by tandem mass spectrometry and liquid chromatography

International Nuclear Information System (INIS)

Chang, Ching-jer; Cooks, R.G.; Chae, Whi-Gun; Wood, J.M.

1989-01-01

Chemical modifications of DNA in vitro could be directly studied by C-13 NMR and P-31 NMR, which eliminated all degradation and separation processes. The prospects of utilized the NMR method in the in vitro experiments are limited because of the inherent low sensitivity of NMR and low level of DNA modification. We have developed a reverse-phase ion-paired HPLC method to study DNA modifications by methylating agents. The structural specificity of HPLC is significantly enhanced by conjunction with the specificity of enzymic transformations. The HPLC studies have also revealed the limitation of HPLC method for simultaneous determination of many minor modified nucleosides. This problem has been overcome by tandem mass spectrometry. In conjunction with the resolving power of HPLC in separating isomers, desorption chemical ionization tandem mass spectrometry has been utilized in the determination of the modified nucleosides at the picomole level using stable-isotope labeled compounds as internal references

Identification of the chemical constituents of Chinese medicine Yi-Xin-Shu capsule by molecular feature orientated precursor ion selection and tandem mass spectrometry structure elucidation.

Science.gov (United States)

Wang, Hong-ping; Chen, Chang; Liu, Yan; Yang, Hong-Jun; Wu, Hong-Wei; Xiao, Hong-Bin

2015-11-01

The incomplete identification of the chemical components of traditional Chinese medicinal formula has been one of the bottlenecks in the modernization of traditional Chinese medicine. Tandem mass spectrometry has been widely used for the identification of chemical substances. Current automatic tandem mass spectrometry acquisition, where precursor ions were selected according to their signal intensity, encounters a drawback in chemical substances identification when samples contain many overlapping signals. Compounds in minor or trace amounts could not be identified because most tandem mass spectrometry information was lost. Herein, a molecular feature orientated precursor ion selection and tandem mass spectrometry structure elucidation method for complex Chinese medicine chemical constituent analysis was developed. The precursor ions were selected according to their two-dimensional characteristics of retention times and mass-to-charge ratio ranges from herbal compounds, so that all precursor ions from herbal compounds were included and more minor chemical constituents in Chinese medicine were identified. Compared to the conventional automatic tandem mass spectrometry setups, the approach is novel and can overcome the drawback for chemical substances identification. As an example, 276 compounds from the Chinese Medicine of Yi-Xin-Shu capsule were identified. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrospray ionization tandem mass spectrometry of ammonium cationized polyethers.

Science.gov (United States)

Nasioudis, Andreas; Heeren, Ron M A; van Doormalen, Irene; de Wijs-Rot, Nicolette; van den Brink, Oscar F

2011-05-01

Quaternary ammonium salts (Quats) and amines are known to facilitate the MS analysis of high molar mass polyethers by forming low charge state adduct ions. The formation, stability, and behavior upon collision-induced dissociation (CID) of adduct ions of polyethers with a variety of Quats and amines were studied by electrospray ionization quadrupole time-of-flight, quadrupole ion trap, and linear ion trap tandem mass spectrometry (MS/MS). The linear ion trap instrument was part of an Orbitrap hybrid mass spectrometer that allowed accurate mass MS/MS measurements. The Quats and amines studied were of different degree of substitution, structure, and size. The stability of the adduct ions was related to the structure of the cation, especially the amine's degree of substitution. CID of singly/doubly charged primary and tertiary ammonium cationized polymers resulted in the neutral loss of the amine followed by fragmentation of the protonated product ions. The latter reveals information about the monomer unit, polymer sequence, and endgroup structure. In addition, the detection of product ions retaining the ammonium ion was observed. The predominant process in the CID of singly charged quaternary ammonium cationized polymers was cation detachment, whereas their doubly charged adduct ions provided the same information as the primary and tertiary ammonium cationized adduct ions. This study shows the potential of specific amines as tools for the structural elucidation of high molar mass polyethers. © American Society for Mass Spectrometry, 2011

Binomial probability distribution model-based protein identification algorithm for tandem mass spectrometry utilizing peak intensity information.

Science.gov (United States)

Xiao, Chuan-Le; Chen, Xiao-Zhou; Du, Yang-Li; Sun, Xuesong; Zhang, Gong; He, Qing-Yu

2013-01-04

Mass spectrometry has become one of the most important technologies in proteomic analysis. Tandem mass spectrometry (LC-MS/MS) is a major tool for the analysis of peptide mixtures from protein samples. The key step of MS data processing is the identification of peptides from experimental spectra by searching public sequence databases. Although a number of algorithms to identify peptides from MS/MS data have been already proposed, e.g. Sequest, OMSSA, X!Tandem, Mascot, etc., they are mainly based on statistical models considering only peak-matches between experimental and theoretical spectra, but not peak intensity information. Moreover, different algorithms gave different results from the same MS data, implying their probable incompleteness and questionable reproducibility. We developed a novel peptide identification algorithm, ProVerB, based on a binomial probability distribution model of protein tandem mass spectrometry combined with a new scoring function, making full use of peak intensity information and, thus, enhancing the ability of identification. Compared with Mascot, Sequest, and SQID, ProVerB identified significantly more peptides from LC-MS/MS data sets than the current algorithms at 1% False Discovery Rate (FDR) and provided more confident peptide identifications. ProVerB is also compatible with various platforms and experimental data sets, showing its robustness and versatility. The open-source program ProVerB is available at http://bioinformatics.jnu.edu.cn/software/proverb/ .

Pion-nucleus scattering in the isobar formalism

International Nuclear Information System (INIS)

Moniz, E.J.

1978-06-01

Lectures on the isobar-hole model for pion reactions include the isobar as an explicit degree of freedom and the connection with a purely pion and nucleon system, the formalism and its relation to the pion optical potential, the extended schematic model for pion scattering, a simple spinless s-wave model, application to pion-oxygen 16 scattering and comparison with elastic scattering data. In this way the extent is shown to which microscopic treatment of the many-body dynamics explains the data and the extent to which additional physical input is required. Another test is the various inelastic processes. Inclusive reactions are briefly discussed. 37 references

A Quantitative Tool to Distinguish Isobaric Leucine and Isoleucine Residues for Mass Spectrometry-Based De Novo Monoclonal Antibody Sequencing

Science.gov (United States)

Poston, Chloe N.; Higgs, Richard E.; You, Jinsam; Gelfanova, Valentina; Hale, John E.; Knierman, Michael D.; Siegel, Robert; Gutierrez, Jesus A.

2014-07-01

De novo sequencing by mass spectrometry (MS) allows for the determination of the complete amino acid (AA) sequence of a given protein based on the mass difference of detected ions from MS/MS fragmentation spectra. The technique relies on obtaining specific masses that can be attributed to characteristic theoretical masses of AAs. A major limitation of de novo sequencing by MS is the inability to distinguish between the isobaric residues leucine (Leu) and isoleucine (Ile). Incorrect identification of Ile as Leu or vice versa often results in loss of activity in recombinant antibodies. This functional ambiguity is commonly resolved with costly and time-consuming AA mutation and peptide sequencing experiments. Here, we describe a set of orthogonal biochemical protocols, which experimentally determine the identity of Ile or Leu residues in monoclonal antibodies (mAb) based on the selectivity that leucine aminopeptidase shows for n-terminal Leu residues and the cleavage preference for Leu by chymotrypsin. The resulting observations are combined with germline frequencies and incorporated into a logistic regression model, called Predictor for Xle Sites (PXleS) to provide a statistical likelihood for the identity of Leu at an ambiguous site. We demonstrate that PXleS can generate a probability for an Xle site in mAbs with 96% accuracy. The implementation of PXleS precludes the expression of several possible sequences and, therefore, reduces the overall time and resources required to go from spectra generation to a biologically active sequence for a mAb when an Ile or Leu residue is in question.

Generalized model development for a cryo-adsorber and 1-D results for the isobaric refueling period

Energy Technology Data Exchange (ETDEWEB)

Kumar, V. Senthil [India Science Lab, General Motors Global R and D, Creator Building, International Technology Park, Bangalore 560066 (India); Kumar, Sudarshan [Chemical Sciences and Material Systems Lab, General Motors Global R and D, Warren Technical Center Campus, 30500 Mound Road, Warren, MI 48090 (United States)

2010-04-15

We have developed 3-D model equations for a cryo-adsorption hydrogen storage tank, where the energy balance accommodates the temperature and pressure variation of all the thermodynamic properties. We then reduce the 3-D model to the 1-D isobaric system and study the isobaric refueling period, for simplified geometry and charging conditions. The hydrogen capacity evolution predicted by the 1-D axial bed model is significantly different than that predicted by the lumped-parameter model because of the presence of sharp temperature gradients during refueling. The 1-D model predicts a higher hydrogen capacity than the lumped-parameter model. This observation can be rationalized by the fact that a bed with temperature gradients on equilibration should desorb gas, whenever the adsorbed phase entropy is lower than the gas phase entropy. The 1-D analysis of the isobaric refueling period does not show any significant difference in hydrogen capacity evolution among the axial, single and multicartridge annular bed designs. Hence, a multicartridge annular design, though giving a slightly lower pressure drop, does not offer any heat and mass transfer enhancement over the single cartridge design. And, the single cartridge annular design appears to be optimal. (author)

Isobars and the Efficient Market Hypothesis

OpenAIRE

Kristýna Ivanková

2010-01-01

Isobar surfaces, a method for describing the overall shape of multidimensional data, are estimated by nonparametric regression and used to evaluate the efficiency of selected markets based on returns of their stock market indices.

A dedicated AMS setup for 53Mn/60Fe at the Cologne FN tandem accelerator

Science.gov (United States)

Schiffer, M.; Dewald, A.; Feuerstein, C.; Altenkirch, R.; Stolz, A.; Heinze, S.

2015-10-01

Following demands for AMS measurements of medium mass isotopes, especially for 53Mn and 60Fe, we started to build a dedicated AMS setup at the Cologne FN tandem accelerator. This accelerator with a maximum terminal voltage of 10 MV can be reliably operated at a terminal voltage of 9.5 MV which corresponds to energies of 93-102 MeV for 60Fe or 53Mn beams using the 9+ or 10+ charge state. These charge states can be obtained by foil stripping with efficiencies of 30% and 20%, respectively. Energies around 100 MeV are sufficient to effectively suppress the stable isobars 60Ni and 53Cr by (dE/dx) techniques using combinations of energy degrader foils and dispersive elements like electrostatic analyzers and time of flight (TOF) systems as well as (dE/dx)E ion detectors. In this contribution we report on the actual status of the AMS setup and discuss details and expected features.

Cytokinin profiling in plant tissues using ultra-performance liquid chromatography–electrospray tandem mass spectrometry

Czech Academy of Sciences Publication Activity Database

Novák, Ondřej; Hauserová, Eva; Amakorová, Petra; Doležal, Karel; Strnad, Miroslav

2008-01-01

Roč. 69, č. 11 (2008), s. 2214-2224 ISSN 0031-9422 R&D Projects: GA AV ČR KAN200380801 Institutional research plan: CEZ:AV0Z50380511 Keywords : Ultra-performance liquid chromatography (UPLC) * Tandem mass spectrometry (MS/MS) * Microextraction Subject RIV: EC - Immunology Impact factor: 2.946, year: 2008

Liquid Chromatography-Tandem Mass Spectrometry: An Emerging Technology in the Toxicology Laboratory.

Science.gov (United States)

Zhang, Yan Victoria; Wei, Bin; Zhu, Yu; Zhang, Yanhua; Bluth, Martin H

2016-12-01

In the last decade, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen enormous growth in routine toxicology laboratories. LC-MS/MS offers significant advantages over other traditional testing, such as immunoassay and gas chromatography-mass spectrometry methodologies. Major strengths of LC-MS/MS include improvement in specificity, flexibility, and sample throughput when compared with other technologies. Here, the basic principles of LC-MS/MS technology are reviewed, followed by advantages and disadvantages of this technology compared with other traditional techniques. In addition, toxicology applications of LC-MS/MS for simultaneous detection of large panels of analytes are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

Conception of PIPERADE: A high-capacity Penning-trap mass separator for high isobaric contamination at DESIR

Energy Technology Data Exchange (ETDEWEB)

Minaya Ramirez, E., E-mail: minaya@ipno.in2p3.fr [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Alfaurt, P.; Aouadi, M.; Ascher, P.; Blank, B. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Blaum, K. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Cam, J.-F. [Laboratoire de Physique Corpusculaire, Caen (France); Chauveau, P. [Grand Accélérateur National d’Ions Lourds CEA/DSM-CNRS-IN2P3, Caen (France); Daudin, L. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Delahaye, P. [Grand Accélérateur National d’Ions Lourds CEA/DSM-CNRS-IN2P3, Caen (France); Delalee, F. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Dupré, P. [Centre de Sciences Nucléaires et de Sciences de la Matière, Orsay (France); El Abbeir, S.; Gerbaux, M.; Grévy, S.; Guérin, H. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan (France); Lunney, D. [Centre de Sciences Nucléaires et de Sciences de la Matière, Orsay (France); Metz, F. [Max-Planck-Institut für Kernphysik, 69117 Heidelberg (Germany); Naimi, S. [Riken, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Perrot, L. [Institut de Physique Nucléaire, Orsay (France); and others

2016-06-01

The DESIR (decay, excitation and storage of radioactive ions) facility at GANIL-SPIRAL2 will receive a large variety of exotic nuclei at low energy (up to 60 keV) with high intensities. However, the production methods of radioactive beams are non selective, limiting the purity of the beams of interest. Moreover, the high precision needed for nuclear structure and astrophysics studies using beta decay spectroscopy, laser spectroscopy and trap-based experiments at DESIR requires highly pure samples of exotic nuclei. The aim of the double-Pennig-trap mass separator PIPERADE is to deliver large and very pure samples of exotic nuclei to the different experiments in DESIR. New excitation schemes and a large inner diameter of the first trap will mitigate space charge effects to attempt trapping of up to 10{sup 5} ions per pulse. The purification cycle will be performed in a few milliseconds so that short-lived nuclei can be purified. To extract the nuclides of interest from the large amount of isobaric contaminants, a resolving power of 10{sup 5} is mandatory. Afterwards the ions of interest will be accumulated in the second trap until they constitute a sufficiently pure sample for the measurements. The status of the project is presented.

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.

Techniques of tandem accelerator mass spectrometry and their applications to 14C measurements

International Nuclear Information System (INIS)

Nakamura, Toshio; Nakai, Nobuyuki; Furukawa, Michiaki

1990-01-01

A tandem accelerator mass spectrometer, named Tandetron was installed at Nagoya University in 1982 for 14 C measurement. The Tandetron spectrometer consists of a Cs sputter ion source to produce negative carbon ions, a Schenkel-type 2.2 MV tandem accelerator, an ion-beam analyzing apparatus with a charge-energy selector and mass spectrometer, and a heavy ion detector to identify and count 14 C 3+ ions from various background ions. The 14 C concentrations in pine needles, sampled at the Higashiyama Campus of Nagoya University, have been measured since 1984. The present article describes some of the measurements of 14 C in pine needles, focusing on the annual changes in the Δ 14 C value of atmospheric CO 2 , and on the effect upon 14 C concentrations for pine needles of a local 14 CO 2 emission from incineration of radioactive organic solvent wastes containing 14 C, at the Radioisotope Center in the Higashiyama Campus. The pine needles at some locations seemed to be influenced by local artificial CO 2 emission. The Δ 14 C values increased noticeably from 1956 to 1964 as a result of artificial 14 C produced in nuclear weapon tests. (N.K.)

An Automated, High-Throughput Method for Interpreting the Tandem Mass Spectra of Glycosaminoglycans

Science.gov (United States)

Duan, Jiana; Jonathan Amster, I.

2018-05-01

The biological interactions between glycosaminoglycans (GAGs) and other biomolecules are heavily influenced by structural features of the glycan. The structure of GAGs can be assigned using tandem mass spectrometry (MS2), but analysis of these data, to date, requires manually interpretation, a slow process that presents a bottleneck to the broader deployment of this approach to solving biologically relevant problems. Automated interpretation remains a challenge, as GAG biosynthesis is not template-driven, and therefore, one cannot predict structures from genomic data, as is done with proteins. The lack of a structure database, a consequence of the non-template biosynthesis, requires a de novo approach to interpretation of the mass spectral data. We propose a model for rapid, high-throughput GAG analysis by using an approach in which candidate structures are scored for the likelihood that they would produce the features observed in the mass spectrum. To make this approach tractable, a genetic algorithm is used to greatly reduce the search-space of isomeric structures that are considered. The time required for analysis is significantly reduced compared to an approach in which every possible isomer is considered and scored. The model is coded in a software package using the MATLAB environment. This approach was tested on tandem mass spectrometry data for long-chain, moderately sulfated chondroitin sulfate oligomers that were derived from the proteoglycan bikunin. The bikunin data was previously interpreted manually. Our approach examines glycosidic fragments to localize SO3 modifications to specific residues and yields the same structures reported in literature, only much more quickly.

High Precision Atomic Mass Measurements: Tests of CVC and IMME

International Nuclear Information System (INIS)

Eronen, Tommi

2011-01-01

Atomic mass is one of the key ingredients in testing the Conserved Vector Current (CVC) hypothesis and Isobaric Mass Multiplet Equation (IMME). With JYFLTRAP Penning trap installation at the University of Jyvaeskylae, Finland, several atomic massses related to these studies have been measured. The performed atomic mass measurements for CVC tests cover almost all the nuclei that are relevant for these studies. To test IMME, masses in two isobaric mass chains (A = 23 and A = 32) have been determined.

High Precision Atomic Mass Measurements: Tests of CVC and IMME

Energy Technology Data Exchange (ETDEWEB)

Eronen, Tommi [Department of Physics, University of Jyvaeskylae, FI-40014 University of Jyvaeskylae (Finland); Collaboration: JYFLTRAP Collaboration

2011-11-30

Atomic mass is one of the key ingredients in testing the Conserved Vector Current (CVC) hypothesis and Isobaric Mass Multiplet Equation (IMME). With JYFLTRAP Penning trap installation at the University of Jyvaeskylae, Finland, several atomic massses related to these studies have been measured. The performed atomic mass measurements for CVC tests cover almost all the nuclei that are relevant for these studies. To test IMME, masses in two isobaric mass chains (A = 23 and A = 32) have been determined.

Analysis of small carbohydrates in several bioactive botanicals by gas chromatography with mass spectrometry and liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Moldoveanu, Serban; Scott, Wayne; Zhu, Jeff

2015-11-01

Bioactive botanicals contain natural compounds with specific biological activity, such as antibacterial, antioxidant, immune stimulating, and taste improving. A full characterization of the chemical composition of these botanicals is frequently necessary. A study of small carbohydrates from the plant materials of 18 bioactive botanicals is further described. The study presents the identification of the carbohydrate using a gas chromatographic-mass spectrometric analysis that allows detection of molecules as large as maltotetraose, after changing them into trimethylsilyl derivatives. A number of carbohydrates in the plant (fructose, glucose, mannose, sucrose, maltose, xylose, sorbitol, and myo-, chiro-, and scyllo-inositols) were quantitated using a novel liquid chromatography with tandem mass spectrometric technique. Both techniques involved new method developments. The gas chromatography with mass spectrometric analysis involved derivatization and separation on a Rxi(®)-5Sil MS column with H2 as a carrier gas. The liquid chromatographic separation was obtained using a hydrophilic interaction type column, YMC-PAC Polyamine II. The tandem mass spectrometer used an electrospray ionization source in multiple reaction monitoring positive ion mode with the detection of the adducts of the carbohydrates with Cs(+) ions. The validated quantitative procedure showed excellent precision and accuracy allowing the analysis in a wide range of concentrations of the analytes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A comparison of freezing-damage during isochoric and isobaric freezing of the potato

OpenAIRE

Lyu, Chenang; Nastase, Gabriel; Ukpai, Gideon; Serban, Alexandru; Rubinsky, Boris

2017-01-01

Background Freezing is commonly used for food preservation. It is usually done under constant atmospheric pressure (isobaric). While extending the life of the produce, isobaric freezing has detrimental effects. It causes loss of food weight and changes in food quality. Using thermodynamic analysis, we have developed a theoretical model of the process of freezing in a constant volume system (isochoric). The mathematical model suggests that the detrimental effects associated with isobaric freez...

Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

Science.gov (United States)

This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

Probabilistic consensus scoring improves tandem mass spectrometry peptide identification.

Science.gov (United States)

Nahnsen, Sven; Bertsch, Andreas; Rahnenführer, Jörg; Nordheim, Alfred; Kohlbacher, Oliver

2011-08-05

Database search is a standard technique for identifying peptides from their tandem mass spectra. To increase the number of correctly identified peptides, we suggest a probabilistic framework that allows the combination of scores from different search engines into a joint consensus score. Central to the approach is a novel method to estimate scores for peptides not found by an individual search engine. This approach allows the estimation of p-values for each candidate peptide and their combination across all search engines. The consensus approach works better than any single search engine across all different instrument types considered in this study. Improvements vary strongly from platform to platform and from search engine to search engine. Compared to the industry standard MASCOT, our approach can identify up to 60% more peptides. The software for consensus predictions is implemented in C++ as part of OpenMS, a software framework for mass spectrometry. The source code is available in the current development version of OpenMS and can easily be used as a command line application or via a graphical pipeline designer TOPPAS.

Hard breakup of the deuteron into two Δ isobars

International Nuclear Information System (INIS)

Granados, Carlos G.; Sargsian, Misak M.

2011-01-01

We study high-energy photodisintegration of the deuteron into two Δ isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn→ΔΔ scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn→ΔΔ scattering. We predict that the cross section of the deuteron breakup to Δ ++ Δ - is 4-5 times larger than that of the breakup to the Δ + Δ 0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard Δ isobars are the result of the disintegration of the preexisting ΔΔ components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both Δ ++ Δ - and Δ + Δ 0 channels to be similar.

Three-nucleon hadronic and electromagnetic reactions with Δ-isobar excitation

International Nuclear Information System (INIS)

Deltuva, A.; Adam, J. Jr.; Fonseca, A.C.; Sauer, P.U.

2005-01-01

Three-nucleon hadronic and electromagnetic reactions are described. The description uses the purely nucleonic charge-dependent CD-Bonn potential and its coupled-channel extension CD-Bonn + Δ. Exact solutions of three-particle equations are employed for the initial and final states of the reactions. The Δ-isobar excitation yields an effective three-nucleon force and effective two- and three-nucleon currents beside other Δ-isobar effects; they are mutually consistent

Evaluation of the sensitivity of the 'Wiley registry of tandem mass spectral data, MSforID' with MS/MS data of the 'NIST/NIH/EPA mass spectral library'.

Science.gov (United States)

Oberacher, Herbert; Whitley, Graeme; Berger, Bernd

2013-04-01

Tandem mass spectral libraries are versatile tools for small molecular identification finding application in forensic science, doping control, drug monitoring, food and environmental analysis, as well as metabolomics. Two important libraries are the 'Wiley Registry of Tandem Mass Spectral Data, MSforID' (Wiley Registry MSMS) and the collection of MS/MS spectra part of the 2011 edition of the 'NIST/NIH/EPA Mass Spectral Library' (NIST 11 MSMS). Herein, the sensitivity and robustness of the Wiley Registry MSMS were evaluated using spectra extracted from the NIST 11 MSMS library. The sample set was found to be heterogeneous in terms of mass spectral resolution, type of CID, as well as applied collision energies. Nevertheless, sensitive compound identification with a true positive identification rate ≥95% was possible using either the MSforID Search program or the NIST MS Search program 2.0g for matching. To rate the performance of the Wiley Registry MSMS, cross-validation experiments were repeated using subcollections of NIST 11 MSMS as reference library and spectra extracted from the Wiley Registry MSMS as positive controls. Unexpectedly, with both search algorithms tested, correct results were obtained in less than 88% of cases. We examined possible causes for the results of the cross validation study. The large number of precursor ions represented by a single tandem mass spectrum only was identified as the basic cause for the comparably lower sensitivity of the NIST library. Copyright © 2013 John Wiley & Sons, Ltd.

Structural analysis of isomeric chondroitin sulfate oligosaccharides using regioselective 6-O-desulfation method and tandem mass spectrometry.

Science.gov (United States)

Chen, Shu-Ting; Her, Guor-Rong

2014-09-16

A strategy based on a regioselective 6-O-desulfation reaction and negative ion electrospray ionization tandem mass spectrometry (ESI-MS(n)) was developed for the structural delineation of isomeric chondroitin sulfate oligosaccharides. Product ions resulting from the glycosidic cleavage provided information about the number of sulfate groups in each sugar residue. After the regioselective 6-O-desulfation reaction, the number of sulfate groups on each residue was obtained using a tandem mass spectrometry analysis of the reaction product. The sulfation pattern could be obtained based on the product ions of analytes before and after the desulfation reaction. The strategy was demonstrated using a series of tetrasaccharides prepared from shark cartilage chondroitin sulfate D. Among the 12 identified tetrasaccharides, six structures had not been reported before. Copyright © 2014 Elsevier B.V. All rights reserved.

FAST DETECTION OF ACETYLSALICYLIC ACID BY LIQUID CHROMATOGRAPHY TANDEM MASS SPECTROMETRY(LC-MSMS)

OpenAIRE

Abusoglu, Sedat; Unlu, Ali; Sivrikaya, Abdullah

2018-01-01

ObjectivesAcetylsalicylic acid (ASA) is themost widely used as an analgesic, anti-inflammatory and antipyretic drug, andalso used to inhibit cyclooxygenase dependent platelet aggregation.   The aimof this study was to develop a simple, fast and accurate tandem mass method fordetermination and quantification of ASA.  MethodsChromatographic seperation was performedusing an Shimadzu LC-20-AD (Kyoto, Japan) coupledwith a ABSCIEX API 3200 triple quadrupole massspectromete...

Screening newborns for metabolic disorders based on targeted metabolomics using tandem mass spectrometry

OpenAIRE

Yoon, Hye-Ran

2015-01-01

The main purpose of newborn screening is to diagnose genetic, metabolic, and other inherited disorders, at their earliest to start treatment before the clinical manifestations become evident. Understanding and tracing the biochemical data obtained from tandem mass spectrometry is vital for early diagnosis of metabolic diseases associated with such disorders. Accordingly, it is important to focus on the entire diagnostic process, including differential and confirmatory diagnostic options, and ...

Mesonic and isobar modes in matter

International Nuclear Information System (INIS)

Riek, Felix C.

2007-01-01

Experiments with heavy ion collisions, like the ones performed at the GSI, are a tool to gain insight in the structure of matter. One key point needed to understand the experimental data is the theoretical description of the in medium properties of mesons and baryons. In this thesis we first developed a self-consistent description for the light vector mesons, ρ and ω, and the pion at finite temperature and in a baryon free environment. A generalisation of these calculations towards finite densities mandatorily needs a reliable description for the pion and the Δ(1232) resonance. Here we extended the approaches discussed in literature by the inclusion of vertex corrections and a selfconsistent and completely relativistic description. Within these models we were able to show that even at high temperatures the ρ-meson properties are not changed dramatically when temperature effects are considered only. In contrast to this the behaviour of the pion and the Δ-isobar is dramatically changed a finite density. The isobar mass-shift is given by an appropriate choice of the mean-fields. Therefore we can not draw a final conclusion about such shifts within our model. In order to do so more calculations, especially of the photo absorption on the nucleus, have to be performed. A further aspect of the calculations presented is that due to a consistent consideration of vertex corrections we were able to achieve a description of the Δ-resonance without the usually used soft formfactor. This is especially important for the in-medium calculations because only in this way we can guarantee that soft modes of the spectrum are treated consistently. The techniques developed within this thesis allow for a straight forward generalisation of the presented models with respect to the consideration of more resonances or couplings. Doing so the here obtained description of the in-medium properties of the considered particles can be refined. (orig.)

Mesonic and isobar modes in matter

Energy Technology Data Exchange (ETDEWEB)

Riek, Felix C.

2007-07-01

Experiments with heavy ion collisions, like the ones performed at the GSI, are a tool to gain insight in the structure of matter. One key point needed to understand the experimental data is the theoretical description of the in medium properties of mesons and baryons. In this thesis we first developed a self-consistent description for the light vector mesons, {rho} and {omega}, and the pion at finite temperature and in a baryon free environment. A generalisation of these calculations towards finite densities mandatorily needs a reliable description for the pion and the {delta}(1232) resonance. Here we extended the approaches discussed in literature by the inclusion of vertex corrections and a selfconsistent and completely relativistic description. Within these models we were able to show that even at high temperatures the {rho}-meson properties are not changed dramatically when temperature effects are considered only. In contrast to this the behaviour of the pion and the {delta}-isobar is dramatically changed a finite density. The isobar mass-shift is given by an appropriate choice of the mean-fields. Therefore we can not draw a final conclusion about such shifts within our model. In order to do so more calculations, especially of the photo absorption on the nucleus, have to be performed. A further aspect of the calculations presented is that due to a consistent consideration of vertex corrections we were able to achieve a description of the {delta}-resonance without the usually used soft formfactor. This is especially important for the in-medium calculations because only in this way we can guarantee that soft modes of the spectrum are treated consistently. The techniques developed within this thesis allow for a straight forward generalisation of the presented models with respect to the consideration of more resonances or couplings. Doing so the here obtained description of the in-medium properties of the considered particles can be refined. (orig.)

Quantitative analysis of phytosterols in edible oils using APCI liquid chromatography-tandem mass spectrometry

Science.gov (United States)

Mo, Shunyan; Dong, Linlin; Hurst, W. Jeffrey; van Breemen, Richard B.

2014-01-01

Previous methods for the quantitative analysis of phytosterols have usually used GC-MS and require elaborate sample preparation including chemical derivatization. Other common methods such as HPLC with absorbance detection do not provide information regarding the identity of the analytes. To address the need for an assay that utilizes mass selectivity while avoiding derivatization, a quantitative method based on LC-tandem mass spectrometry (LC-MS-MS) was developed and validated for the measurement of six abundant dietary phytosterols and structurally related triterpene alcohols including brassicasterol, campesterol, cycloartenol, β-sitosterol, stigmasterol, and lupeol in edible oils. Samples were saponified, extracted with hexane and then analyzed using reversed phase HPLC with positive ion atmospheric pressure chemical ionization tandem mass spectrometry and selected reaction monitoring. The utility of the LC-MS-MS method was demonstrated by analyzing 14 edible oils. All six compounds were present in at least some of the edible oils. The most abundant phytosterol in all samples was β-sitosterol, which was highest in corn oil at 4.35 ± 0.03 mg/g, followed by campesterol in canola oil at 1.84 ± 0.01 mg/g. The new LC-MS-MS method for the quantitative analysis of phytosterols provides a combination of speed, selectivity and sensitivity that exceed those of previous assays. PMID:23884629

Tandem mass spectrometric characterization of the conversion of xylose to furfural

International Nuclear Information System (INIS)

Vinueza, Nelson R.; Kim, Eurick S.; Gallardo, Vanessa A.; Mosier, Nathan S.; Abu-Omar, Mahdi M.; Carpita, Nicholas C.; Kenttämaa, Hilkka I.

2015-01-01

Thermal decomposition of xylose into furfural under acidic conditions has been studied using tandem mass spectrometry. Two different Brønsted acids, maleic and sulfuric acids, were used to demonstrate that varying the Brønsted acid does not affect the mechanism of the reaction. Two selectively labeled xylose molecules, 1- 13 C and 5- 13 C-xyloses, were examined to determine which carbon atom is converted to the aldehyde carbon in furfural. This can be done by using tandem mass spectrometry since collision-activated dissociation (CAD) of protonated unlabeled furfural results in the loss of CO from the aldehyde moiety. The loss of a neutral molecule with MW of 29 Da ( 13 CO) was observed for protonated furfural derived from 1- 13 C-labeled xylose while the loss of a neutral molecule with MW of 28 Da (CO) was observed for protonated furfural derived from 5- 13 C labeled xylose. These results support the hypothesis that the mechanism of formation of furfural under mildly hot acidic conditions involves an intramolecular rearrangement of protonated xylose into the pyranose form rather than into an open-chain form. - Highlights: • Mechanism of catalytic conversion of Xyl to furfural under acidic conditions was studied by MS/MS and partially labeled Xyl. • The type of acid does not have a strong influence on the mechanism of catalytic conversion of Xyl to furfural. • The mechanism of formation of furfural under mildly hot acidic conditions involves an intramolecular rearrangement of Xyl

Effect of Δ-isobar excitation on spin-dependent observables of elastic nucleon-deuteron scattering

International Nuclear Information System (INIS)

Nemoto, S.; Oryu, S.; Chmielewski, K.; Sauer, P.U.

2000-01-01

Δ-isobar excitation in the nuclear medium yields an effective three-nucleon force. A coupled-channel formulation with Δ-isobar excitation developed previously is used. The three-particle scattering equations are solved by a separable expansion of the two-baryon transition matrix for elastic nucleon-deuteron scattering. The effect of Δ-isobar excitation on the spin-dependent observables is studied at energies above 50 MeV nucleon lab energy. (author)

Dense strongly non-ideal plasma generation by laser isobaric heating

International Nuclear Information System (INIS)

Kulik, P.P.; Rozanov, E.K.; Riabii, V.A.; Titov, M.A.

1975-01-01

A method of generation of a dense strongly non-ideal plasma by slow isobaric heating of a small target in a high inert gas medium is discussed. The characteristic life-time of dense plasma is 10 -3 sec. Estimations show that such a plasma is homogeneous. Conditions are found for temperature uniformity. The experimental results of the isobaric heating of a thin potassium foil target by a ruby laser beam at 500 atm are described. (Auth.)

Authentication of Closely Related Fish and Derived Fish Products Using Tandem Mass Spectrometry and Spectral Library Matching

NARCIS (Netherlands)

Nessen, Merel A.; Zwaan, van der Dennis J.; Grevers, Sander; Dalebout, Hans; Staats, Martijn; Kok, Esther; Palmblad, Magnus

2016-01-01

Proteomics methodology has seen increased application in food authentication, including tandem mass spectrometry of targeted species-specific peptides in raw, processed, or mixed food products. We have previously described an alternative principle that uses untargeted data acquisition and

Determination of parabens in serum by liquid chromatography-tandem mass spectrometry: Correlation with lipstick use.

Science.gov (United States)

Tahan, Gabriella Padovani; Santos, Nayara de Kássia Souza; Albuquerque, Ana Carolina; Martins, Isarita

2016-08-01

Parabens are the most widely used preservative and are considered to be relatively safe compounds. However, studies have demonstrated that they may have estrogenic activity, and there is ongoing debate regarding the safety and potential cancer risk of using products containing these compounds. In the present work, liquid chromatography-tandem mass spectrometry was applied to determine methylparaben and propylparaben concentrations in serum, and the results were correlated with lipstick application. Samples were analyzed using liquid-liquid extraction, followed by liquid chromatography-tandem mass spectrometry. The validation results demonstrated the linearity of the method over a range of 1-20 ng/mL, in addition to the method's precision and accuracy. A statistically significant difference was demonstrated between serum parabens in women who used lipstick containing these substances compared with those not using this cosmetic (p = 0.0005 and 0.0016, respectively), and a strong association was observed between serum parabens and lipstick use (Spearman correlation = 0.7202). Copyright © 2016 Elsevier Inc. All rights reserved.

Identification of the C3H7 moiety of isopropyl- and propylphosphonates by electrospray tandem mass spectrometry

NARCIS (Netherlands)

Baar, B.L.M. van; Hulst, A.G.; Wils, E.R.J.

1998-01-01

Structure analysis of phosphorus compounds within the framework of the Chemical Weapons Convention requires the specific identification of alkyl substituents on phosphorus. In this work the distinction of the P-propyl substituent in propylphosphonic acid derivatives by electrospray tandem mass

Advanced Laser Architecture for Two-Step Laser Tandem Mass Spectrometer

Science.gov (United States)

Fahey, Molly E.; Li, Steven X.; Yu, Anthony W.; Getty, Stephanie A.

2016-01-01

Future astrobiology missions will focus on planets with significant astrochemical or potential astrobiological features, such as small, primitive bodies and the icy moons of the outer planets that may host diverse organic compounds. These missions require advanced instrument techniques to fully and unambiguously characterize the composition of surface and dust materials. Laser desorptionionization mass spectrometry (LDMS) is an emerging instrument technology for in situ mass analysis of non-volatile sample composition. A recent Goddard LDMS advancement is the two-step laser tandem mass spectrometer (L2MS) instrument to address the need for future flight instrumentation to deconvolve complex organic signatures. The L2MS prototype uses a resonance enhanced multi-photon laser ionization mechanism to selectively detect aromatic species from a more complex sample. By neglecting the aliphatic and inorganic mineral signatures in the two-step mass spectrum, the L2MS approach can provide both mass assignments and clues to structural information for an in situ investigation of non-volatile sample composition. In this paper we will describe our development effort on a new laser architecture that is based on the previously flown Lunar Orbiter Laser Altimeter (LOLA) laser transmitter for the L2MS instrument. The laser provides two discrete midinfrared wavelengths (2.8 m and 3.4 m) using monolithic optical parametric oscillators and ultraviolet (UV) wavelength (266 nm) on a single laser bench with a straightforward development path toward flight readiness.

Characterization of sulfur mustard induced structural modifications in human hemoglobin by liquid chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Noort, D.; Verheij, E.R.; Hulst, A.G.; Jong, L.P.A. de; Benschop, H.P.

1996-01-01

In this paper we describe the use of tandem mass spectrometry to identify modified sites in human hemoglobin after in vitro exposure to bis(2- chloroethyl) sulfide (sulfur mustard). Globin isolated from human whole blood which had been exposed to sulfur mustard was degraded with trypsin, and the

Characterization of cationic glycoporphyrins by electrospray tandem mass spectrometry.

Science.gov (United States)

Silva, Eduarda M P; Serra, Vanda Vaz; Ribeiro, Anderson O; Tomé, João P C; Domingues, Pedro; Faustino, M Amparo F; Neves, M Graça P M S; Tomé, Augusto C; Cavaleiro, José A S; Ferrer-Correia, António J; Iamamoto, Yassuko; Domingues, M Rosário M

2006-01-01

Novel cationic porphyrin derivatives having a galactose or a bis(isopropylidene)galactose unit linked directly to a pyridine or to an aminophenyl group were characterized by electrospray tandem mass spectrometry (ESI-MS/MS). The electrospray mass spectra (ESI-MS) show the M(+) ions, since these porphyrins are already monocharged in solution. The fragmentation of these ions under ESI-MS/MS conditions was studied and it was found that elimination of the sugar residue as a radical (-163 or -243 Da) is a common fragmentation pathway. Loss of the sugar unit as a neutral fragment (-162 or -242 Da) and cross-ring fragmentations typical of glyco-derivatives are also observed for the pyridinium glycoporphyrins, but they are absent in the case of ammonium glycoporphyrins. The cationic beta-pyridiniumvinyl porphyrins show an atypical fragmentation due to the cleavage of the C(5)-C(6) bond of the sugar unit. Overall, the different patterns of fragmentation observed in the ESI-MS/MS spectra of the sugar pyridinium porphyrins and of the sugar ammonium phenyl porphyrins can give important information about the type of spacer between the porphyrin and the sugar unit. Copyright (c) 2006 John Wiley & Sons, Ltd.

Direct Visualization of Neurotransmitters in Rat Brain Slices by Desorption Electrospray Ionization Mass Spectrometry Imaging (DESI - MS)

Science.gov (United States)

Fernandes, Anna Maria A. P.; Vendramini, Pedro H.; Galaverna, Renan; Schwab, Nicolas V.; Alberici, Luciane C.; Augusti, Rodinei; Castilho, Roger F.; Eberlin, Marcos N.

2016-12-01

Mass spectrometry imaging (MSI) of neurotransmitters has so far been mainly performed by matrix-assisted laser desorption/ionization (MALDI) where derivatization reagents, deuterated matrix and/or high resolution, or tandem MS have been applied to circumvent problems with interfering ion peaks from matrix and from isobaric species. We herein describe the application of desorption electrospray ionization mass spectrometry imaging (DESI)-MSI in rat brain coronal and sagittal slices for direct spatial monitoring of neurotransmitters and choline with no need of derivatization reagents and/or deuterated materials. The amino acids γ-aminobutyric (GABA), glutamate, aspartate, serine, as well as acetylcholine, dopamine, and choline were successfully imaged using a commercial DESI source coupled to a hybrid quadrupole-Orbitrap mass spectrometer. The spatial distribution of the analyzed compounds in different brain regions was determined. We conclude that the ambient matrix-free DESI-MSI is suitable for neurotransmitter imaging and could be applied in studies that involve evaluation of imbalances in neurotransmitters levels.

Characterization of Disulfide-Linked Peptides Using Tandem Mass Spectrometry Coupled with Automated Data Analysis Software

Science.gov (United States)

Liang, Zhidan; McGuinness, Kenneth N.; Crespo, Alejandro; Zhong, Wendy

2018-05-01

Disulfide bond formation is critical for maintaining structure stability and function of many peptides and proteins. Mass spectrometry has become an important tool for the elucidation of molecular connectivity. However, the interpretation of the tandem mass spectral data of disulfide-linked peptides has been a major challenge due to the lack of appropriate tools. Developing proper data analysis software is essential to quickly characterize disulfide-linked peptides. A thorough and in-depth understanding of how disulfide-linked peptides fragment in mass spectrometer is a key in developing software to interpret the tandem mass spectra of these peptides. Two model peptides with inter- and intra-chain disulfide linkages were used to study fragmentation behavior in both collisional-activated dissociation (CAD) and electron-based dissociation (ExD) experiments. Fragments generated from CAD and ExD can be categorized into three major types, which result from different S-S and C-S bond cleavage patterns. DiSulFinder is a computer algorithm that was newly developed based on the fragmentation observed in these peptides. The software is vendor neutral and capable of quickly and accurately identifying a variety of fragments generated from disulfide-linked peptides. DiSulFinder identifies peptide backbone fragments with S-S and C-S bond cleavages and, more importantly, can also identify fragments with the S-S bond still intact to aid disulfide linkage determination. With the assistance of this software, more comprehensive disulfide connectivity characterization can be achieved. [Figure not available: see fulltext.

Characterization of Disulfide-Linked Peptides Using Tandem Mass Spectrometry Coupled with Automated Data Analysis Software.

Science.gov (United States)

Liang, Zhidan; McGuinness, Kenneth N; Crespo, Alejandro; Zhong, Wendy

2018-01-25

Disulfide bond formation is critical for maintaining structure stability and function of many peptides and proteins. Mass spectrometry has become an important tool for the elucidation of molecular connectivity. However, the interpretation of the tandem mass spectral data of disulfide-linked peptides has been a major challenge due to the lack of appropriate tools. Developing proper data analysis software is essential to quickly characterize disulfide-linked peptides. A thorough and in-depth understanding of how disulfide-linked peptides fragment in mass spectrometer is a key in developing software to interpret the tandem mass spectra of these peptides. Two model peptides with inter- and intra-chain disulfide linkages were used to study fragmentation behavior in both collisional-activated dissociation (CAD) and electron-based dissociation (ExD) experiments. Fragments generated from CAD and ExD can be categorized into three major types, which result from different S-S and C-S bond cleavage patterns. DiSulFinder is a computer algorithm that was newly developed based on the fragmentation observed in these peptides. The software is vendor neutral and capable of quickly and accurately identifying a variety of fragments generated from disulfide-linked peptides. DiSulFinder identifies peptide backbone fragments with S-S and C-S bond cleavages and, more importantly, can also identify fragments with the S-S bond still intact to aid disulfide linkage determination. With the assistance of this software, more comprehensive disulfide connectivity characterization can be achieved. Graphical Abstract ᅟ.

Screening for estrogen residues in calf urine: Comparison of a validated yeast estrogen bioassay and gas chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Nielen, M.W.F.; Bovee, T.F.H.; Heskamp, H.H.; Lasaroms, J.J.P.; Sanders, M.B.; Rhijn, van J.A.; Groot, M.J.; Hoogenboom, L.A.P.

2006-01-01

Within the European Union, the control for residues of illegal hormones in food-producing animals is based on urine analysis for a few target analytes using gas chromatography/mass spectrometry and/or liquid chromatography¿tandem mass spectrometry. Recently, we developed a robust yeast bioassay

Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry Measurement of Caffeine in Caffeine-Laced Pants and in Urine and Skin of a Pants User

OpenAIRE

Pellegrini, Manuela; Orsi, Daniela De; Guarino, Carmine; Rotolo, Maria; Giovannandrea, Rita di; Pacifici, Roberta; Pichini, Simona

2014-01-01

A fast and sensitive ultra-performance liquid chromatography tandem mass spectrometry method was developed for the measurement of caffeine in caffeine-laced pants and in urine and skin of a pants user. The substance and its internal standard (N-ethylnorcotinine) were separated by reversed phase chromatography with 5 mM ammonium formate pH 3.0 and 0.3% formic acid in acetonitrile mobile phase (83:17 v/v) by isocratic elution and detected by tandem mass spectrometry operated in multiple reacti...

A qualitative study of amlodipine and its related compounds by electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Gibbons, John; Pugh, Jonathan; Dimopoulos-Italiano, Gina; Pike, Richard

2006-01-01

A comprehensive structural analysis of amlodipine and certain related compounds was performed by electrospray ionization tandem mass spectrometry. Triple quadrupole and quadrupole time-of-flight instruments were used to provide collision-induced dissociation and accurate mass measurement for selected product and second-generation product ions. A unique ion rearrangement was observed, which was found to be characteristic of certain dihydropyridines. This study provides a fundamental understanding of the fragmentation of these compounds. The structural elucidation of an unknown impurity is presented as an example. Copyright (c) 2006 John Wiley & Sons, Ltd.

Accelerator mass spectrometry of heavy elements: /sup 36/Cl to /sup 205/Pb

Energy Technology Data Exchange (ETDEWEB)

Henning, W

1987-08-25

Measurements are discussed in which the technique of accelerator mass spectrometry was applied to problems involving heavy radioisotopes. These measurements, which depend on the ion energies that can be reached with the new heavy-ion accelerator facilities, were performed at the Argonne tandem linac accelerator system (ATLAS) and at the UNILAC accelerator at GSI. The topics include a discussion of measurements of long nuclear lifetimes, of radioisotope detection of interest to solar neutrino experiments, and of a determination of the /sup 41/Ca concentration in natural samples of terrestrial origin by making use of isotopic pre-enrichment in an isotope separator. A long-known method of isobar separation, employing a gas-filled magnetic field region, has been revived for some of these measurements and its characteristics and advantages are briefly reviewed.

Liquid chromatography coupled with tandem mass spectrometry for the quantitative analysis of anticancer drugs in biological matrices

NARCIS (Netherlands)

Stokvis, Ellen

2004-01-01

In this thesis, the development and validation of liquid chromatography tandem mass spectrometric (LC-MS/MS) methods for the quantitative bioanalysis of anticancer drugs are described. The monitoring of these drugs in biological fluids and tissues is important during both pre-clinical and clinical

Ariadne: a database search engine for identification and chemical analysis of RNA using tandem mass spectrometry data.

Science.gov (United States)

Nakayama, Hiroshi; Akiyama, Misaki; Taoka, Masato; Yamauchi, Yoshio; Nobe, Yuko; Ishikawa, Hideaki; Takahashi, Nobuhiro; Isobe, Toshiaki

2009-04-01

We present here a method to correlate tandem mass spectra of sample RNA nucleolytic fragments with an RNA nucleotide sequence in a DNA/RNA sequence database, thereby allowing tandem mass spectrometry (MS/MS)-based identification of RNA in biological samples. Ariadne, a unique web-based database search engine, identifies RNA by two probability-based evaluation steps of MS/MS data. In the first step, the software evaluates the matches between the masses of product ions generated by MS/MS of an RNase digest of sample RNA and those calculated from a candidate nucleotide sequence in a DNA/RNA sequence database, which then predicts the nucleotide sequences of these RNase fragments. In the second step, the candidate sequences are mapped for all RNA entries in the database, and each entry is scored for a function of occurrences of the candidate sequences to identify a particular RNA. Ariadne can also predict post-transcriptional modifications of RNA, such as methylation of nucleotide bases and/or ribose, by estimating mass shifts from the theoretical mass values. The method was validated with MS/MS data of RNase T1 digests of in vitro transcripts. It was applied successfully to identify an unknown RNA component in a tRNA mixture and to analyze post-transcriptional modification in yeast tRNA(Phe-1).

Clustering and Filtering Tandem Mass Spectra Acquired in Data-Independent Mode

Science.gov (United States)

Pak, Huisong; Nikitin, Frederic; Gluck, Florent; Lisacek, Frederique; Scherl, Alexander; Muller, Markus

2013-12-01

Data-independent mass spectrometry activates all ion species isolated within a given mass-to-charge window ( m/z) regardless of their abundance. This acquisition strategy overcomes the traditional data-dependent ion selection boosting data reproducibility and sensitivity. However, several tandem mass (MS/MS) spectra of the same precursor ion are acquired during chromatographic elution resulting in large data redundancy. Also, the significant number of chimeric spectra and the absence of accurate precursor ion masses hamper peptide identification. Here, we describe an algorithm to preprocess data-independent MS/MS spectra by filtering out noise peaks and clustering the spectra according to both the chromatographic elution profiles and the spectral similarity. In addition, we developed an approach to estimate the m/z value of precursor ions from clustered MS/MS spectra in order to improve database search performance. Data acquired using a small 3 m/z units precursor mass window and multiple injections to cover a m/z range of 400-1400 was processed with our algorithm. It showed an improvement in the number of both peptide and protein identifications by 8 % while reducing the number of submitted spectra by 18 % and the number of peaks by 55 %. We conclude that our clustering method is a valid approach for data analysis of these data-independent fragmentation spectra. The software including the source code is available for the scientific community.

Isobaric expansion coefficient and isothermal compressibility for a finite-size ideal Fermi gas system

International Nuclear Information System (INIS)

Su, Guozhen; Chen, Liwei; Chen, Jincan

2014-01-01

Due to quantum size effects (QSEs), the isobaric thermal expansion coefficient and isothermal compressibility well defined for macroscopic systems are invalid for finite-size systems. The two parameters are redefined and calculated for a finite-size ideal Fermi gas confined in a rectangular container. It is found that the isobaric thermal expansion coefficient and isothermal compressibility are generally anisotropic, i.e., they are generally different in different directions. Moreover, it is found the thermal expansion coefficient may be negative in some directions under the condition that the pressures in all directions are kept constant. - Highlights: • Isobaric thermal expansion coefficient and isothermal compressibility are redefined. • The two parameters are calculated for a finite-size ideal Fermi gas. • The two parameters are generally anisotropic for a finite-size system. • Isobaric thermal expansion coefficient may be negative in some directions

Mass- and energy-dependence of (π+,π-) double isobaric analog transitions at low energies

International Nuclear Information System (INIS)

Anderl, T.

1988-01-01

Transitions to double isobaric analog states (DIAT) have been measured in the double charge exchange (DCX) reaction (π + ,π - ) for the nuclei 26 Mg, 56 Fe at Tsub(π+) = 49 MeV and for 18 O at Tsub(π+) = 24 MeV, 33 MeV, 49 MeV, 64 MeV and 79 MeV for several angles. The experiments have been performed at the pion channels M13 and M11 of TRIUMF using the low energy pion spectrometer QQD. The forward angle cross sections for 18 O can be understood in a quark model as well as in conventional models where the reaction is mainly proceeding through intermediate deltas or low lying excited states of the intermediate nucleus. The angular distribution of 26 Mg at 49 MeV is found to be almost identical to those of 14 C and 18 O while the cross section remarkedly drops for 56 Fe. The forward angle excitation function of 18 O exhibits a maximum at around 35 MeV. The present results are compared to theoretical predictions. Two approaches for a unified study of SCX and DCX at energies ranging from 20 MeV up to 300 MeV are presented. The first is carried out in a mean free path model for investigations of geometry effects in the reaction. For the second, the optical model code PIESDEX is employed. Both studies indicate that the observed mass dependence for DCX at 50 MeV can be explained partly by geometry considerations and partly by details in the nuclear matter distributions of core neutrons and valence neutrons. Furthermore, the optical model investigation reveals the need of shifting the free πN-SCX amplitude down by 30 MeV in order to achieve good agreement with experimental data. (orig.)

Isobaric yield ratios and the symmetry energy in heavy-ion reactions near the Fermi energy

International Nuclear Information System (INIS)

Huang, M.; Chen, Z.; Kowalski, S.; Ma, Y. G.; Wada, R.; Hagel, K.; Barbui, M.; Bottosso, C.; Materna, T.; Natowitz, J. B.; Qin, L.; Rodrigues, M. R. D.; Sahu, P. K.; Keutgen, T.; Bonasera, A.; Wang, J.

2010-01-01

The relative isobaric yields of fragments produced in a series of heavy-ion-induced multifragmentation reactions have been analyzed in the framework of a modified Fisher model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, a sym /T, as a function of fragment mass A. The extracted values increase from 5 to ∼16 as A increases from 9 to 37. These values have been compared to the results of calculations using the antisymmetrized molecular dynamics (AMD) model together with the statistical decay code gemini. The calculated ratios are in good agreement with those extracted from the experiment. In contrast, the values extracted from the ratios of the primary isobars from the AMD model calculation are ∼4 to 5 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.

Identification and High-Resolution Imaging of α-Tocopherol from Human Cells to Whole Animals by TOF-SIMS Tandem Mass Spectrometry

Science.gov (United States)

Bruinen, Anne L.; Fisher, Gregory L.; Balez, Rachelle; van der Sar, Astrid M.; Ooi, Lezanne; Heeren, Ron M. A.

2018-06-01

A unique method for identification of biomolecular components in different biological specimens, while preserving the capability for high speed 2D and 3D molecular imaging, is employed to investigate cellular response to oxidative stress. The employed method enables observing the distribution of the antioxidant α-tocopherol and other molecules in cellular structures via time-of-flight secondary ion mass spectrometry (TOF-SIMS (MS1)) imaging in parallel with tandem mass spectrometry (MS2) imaging, collected simultaneously. The described method is employed to examine a network formed by neuronal cells differentiated from human induced pluripotent stem cells (iPSCs), a model for investigating human neurons in vitro. The antioxidant α-tocopherol is identified in situ within different cellular layers utilizing a 3D TOF-SIMS tandem MS imaging analysis. As oxidative stress also plays an important role in mediating inflammation, the study was expanded to whole body tissue sections of M. marinum-infected zebrafish, a model organism for tuberculosis. The TOF-SIMS tandem MS imaging results reveal an increased presence of α-tocopherol in response to the pathogen. [Figure not available: see fulltext.

Comparative study of intrathecal hyperbaric versus isobaric ropivacaine: A randomized control trial

Directory of Open Access Journals (Sweden)

Rajni Gupta

2013-01-01

Full Text Available Background: Hyperbaric ropivacaine produce more reliable sensory and motor block, with faster onset, better quality of muscles relaxation than isobaric ropivacaine. So, this study was designed to compare the efficacy of hyperbaric ropivacaine with isobaric ropivacaine in patients undergoing lower abdominal surgery. Methods: A randomized controlled double blind study in two groups of patients. group A (n=35 received 3 ml of isobaric ropivacaine 6 mg/ml (18 mg. Group B (n=35 received 3 ml of hyperbaric ropivacaine 6 mg/ml (18 mg. The onset and duration of sensory block at dermatome level T10, maximum upper and lower spread of sensory block, intensity, and duration of motor block were recorded. Statistical Analysis: Block characteristics were compared using the two-tailed Mann - Whitney U-test. The proportion of side effects was compared using the Chi-square test. Results: The median time of onset of sensory block at the T10 dermatome was 4.4±1.3 min in group B and 6.0±1.03 min in group A. The median time to maximum block height was 16.7±3.7 min in group A and 12.03±1.96 min in group B. The median duration of complete motor recovery (B0 was significantly shorter in the heavy ropivacaine group (166.5±11.7 min compared with the isobaric ropivacaine group (192.9±9.6 min. Conclusions: Intrathecal hyperbaric ropivacaine provides more rapid, adequate, and good quality of sensory and motor block with rapid post-operative recovery as compare to isobaric ropivacaine.

Regioisomers of octanoic acid-containing structured triacylglycerols analyzed by tandem mass spectrometry using ammonia negative ion chemical ionization

DEFF Research Database (Denmark)

Kurvinen, J.P.; Mu, Huiling; Kallio, H.

2001-01-01

Tandem mass spectrometry based on ammonia negative ion chemical ionization and sample introduction via direct exposure probe was applied to analysis of regioisomeric structures of octanoic acid containing structured triacylglycerols (TAG) of type MML, MLM, MLL, and LML (M, medium-chain fatty acid...

Charge independence and charge symmetry breaking interactions and the Coulomb energy anomaly in isobaric analog states

International Nuclear Information System (INIS)

Suzuki, Toshio; Sagawa, H.; Giai, N. van.

1992-01-01

Effects of CIB (charge independence breaking) and CSB (charge symmetry breaking) interactions on the Coulomb displacement energies of isobaric analog states are investigated for 48 Ca, 90 Zr and 208 Pb. Mass number dependence of the Coulomb energy anomalies is well explained when CIB and CSB interactions are used which reproduce the differences of the scattering lengths as well as those of the effective ranges of low energy nucleon-nucleon scattering. (author) 17 refs., 3 figs., 3 tabs

Comparison of hypobaric, hyperbaric, and isobaric solutions of bupivacaine during continuous spinal anesthesia.

Science.gov (United States)

Van Gessel, E F; Forster, A; Schweizer, A; Gamulin, Z

1991-06-01

This study was designed to compare the anesthetic properties of hypobaric bupivacaine with those of isobaric and hyperbaric solutions when administered in the supine position in an elderly population undergoing hip surgery using continuous spinal anesthesia. Plain bupivacaine (0.5%) was mixed with equal volumes of 10% dextrose (hyperbaric), 0.9% NaCl (isobaric), or distilled water (hypobaric) to obtain 0.25% solutions. In a double-blind fashion, all patients received 3 mL (7.5 mg) of their particular solution injected through the spinal catheter in the horizontal supine position. The sensory level obtained in the hyperbaric group (median, T4; range, T3-L3) was significantly higher than in both the isobaric (median, T11; range, T6-L1) and hypobaric (median, L1; range, T4-L3) groups. A motor blockade of grade 2 or 3 was obtained in 14 of 15 and 12 of 15 patients in, respectively, the hyperbaric and isobaric groups, but only in 8 of 15 patients in the hypobaric group. After the initial injection of 3 mL (7.5 mg), a sensory level of T10 and a motor blockade of grade 2 or 3 was obtained in 14 of 15, 5 of 15, and 3 of 15 patients in the hyperbaric, isobaric, and hypobaric groups, respectively. All remaining patients received 1 or 2 additional milliliters (2.5-5 mg) and achieved these required anesthetic conditions, except for one patient in the hyperbaric group and eight patients in the hypobaric group in whom anesthesia was achieved with hyperbaric tetracaine. The decrease in mean arterial pressure was significantly more severe in the hyperbaric (30%) than in either the isobaric (18%) or hypobaric (14%) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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

DEFF Research Database (Denmark)

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

2016-01-01

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

Liquid chromatography-tandem mass spectrometry determination of synthetic cathinones and phenethylamines in influent wastewater of eight European cities

DEFF Research Database (Denmark)

Bade, Richard; Bijlsma, Lubertus; Sancho, Juan V.

2017-01-01

(SPE) with Oasis MCX cartridges. Isotopically labelled internal standards were used to correct for matrix effects and potential SPE losses. Following chromatographic separation on a C18 column within 6 min, the compounds were measured by tandem mass spectrometry in positive ionization mode. The method...

Self-energy of the Δ-isobar in nuclear matter for the Paris and the Green-Niskanen-Sainio potentials

International Nuclear Information System (INIS)

Dey, J.; Abdul Matin, M.; Samanta, B.C.

1985-11-01

A coupled channel calculation, with the compensated Paris potential and the isobar transition potential due to Green, Niskanen and Sainio, yields the nucleon and isobar self-energies in nuclear matter. Unlike the Reid soft core, the Paris potential is found to bind the isobar at small momentum by a potential of the order of 10 MeV. The change in the binding energy and the wound integral in nuclear matter, due to the explicit treatment of isobar degrees of freedom, is small. (author)

Amino acid analysis in physiological samples by GC-MS with propyl chloroformate derivatization and iTRAQ-LC-MS/MS.

Science.gov (United States)

Dettmer, Katja; Stevens, Axel P; Fagerer, Stephan R; Kaspar, Hannelore; Oefner, Peter J

2012-01-01

Two mass spectrometry-based methods for the quantitative analysis of free amino acids are described. The first method uses propyl chloroformate/propanol derivatization and gas chromatography-quadrupole mass spectrometry (GC-qMS) analysis in single-ion monitoring mode. Derivatization is carried out directly in aqueous samples, thereby allowing automation of the entire procedure, including addition of reagents, extraction, and injection into the GC-MS. The method delivers the quantification of 26 amino acids. The isobaric tagging for relative and absolute quantification (iTRAQ) method employs the labeling of amino acids with isobaric iTRAQ tags. The tags contain two different cleavable reporter ions, one for the sample and one for the standard, which are detected by fragmentation in a tandem mass spectrometer. Reversed-phase liquid chromatography of the labeled amino acids is performed prior to mass spectrometric analysis to separate isobaric amino acids. The commercial iTRAQ kit allows for the analysis of 42 physiological amino acids with a respective isotope-labeled standard for each of these 42 amino acids.

A high-resolution tandem mass spectrometer for the collision-induced dissociation of large molecule ions

International Nuclear Information System (INIS)

Ouwerkerk, C.E.D.

1988-01-01

Instrumental development in the field of tandem mass spectrometry is described in order to use the technique for the analysis of large organic molecules. Experiments are also described in which the process of collision-induced dissociation (CID) is investigated. The fragmentation pattern of CH 4 + has been measured for three different target gases He, Ar and Xe. From these measurements fragmentation cross sections are calculated. 192 refs.; 47 figs.; 6 tabs

Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry.

Science.gov (United States)

Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M

2017-09-01

Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Screening of carnitine and biotin deficiencies on tandem mass spectrometry.

Science.gov (United States)

Hagiwara, Shin-Ichiro; Kubota, Mitsuru; Nambu, Ryusuke; Kagimoto, Seiichi

2017-04-01

It is important to assess pediatric patients for nutritional deficiency when they are receiving specific interventions, such as enteral feeding. We focused on measurement of C0 and 3-hydroxyisovalerylcarnitine (C5-OH) with tandem mass spectrometry (MS/MS), which is performed as part of the newborn mass screening. The purpose of this study was to investigate the usefulness of MS/MS for screening carnitine and biotin deficiencies. Forty-two children (24 boys, 18 girls) were enrolled between December 2013 and December 2015. Blood tests, including measurement of serum free carnitine via the enzyme cycling method, and acylcarnitine analysis on MS/MS of dried blood spot (DBS), were performed for the evaluation of nutrition status. Median patient age was 2 years (range, 2 months-14 years). Mean serum free carnitine was 41.8 ± 19.2 μmol/L. In six of the 42 patients, serum free carnitine was 1.00 nmol/L. Therapy-resistant eczema was improved by treatment with additional biotin and a non-hydrolyzed formula. C0 and C5-OH, measured on MS/MS of DBS, were useful for screening carnitine and biotin deficiencies. © 2016 Japan Pediatric Society.

Profiling ABA metabolites in Nicotiana tabacum L. leaves by ultra-performance liquid chromatography–electrospray tandem mass spectrometry

Czech Academy of Sciences Publication Activity Database

Turečková, Veronika; Novák, Ondřej; Strnad, Miroslav

2009-01-01

Roč. 80, č. 1 (2009), s. 390-399 ISSN 0039-9140 R&D Projects: GA AV ČR KAN200380801 Institutional research plan: CEZ:AV0Z50380511 Keywords : Abscisic acid * Ultra-performance liquid chromatography (UPLC) * Tandem mass spectrometry (MS/MS) Subject RIV: EC - Immunology Impact factor: 3.290, year: 2009

Accelerator mass analysis at tandem accelerator in Kyoto University

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Masanobu; Tazawa, Yuji; Matsumoto, Hiroshi; Hirose, Masanori [Kyoto Univ. (Japan). Faculty of Science; Ogino, Koya; Kohno, Masuchika; Funaba, Hiroyuki

1996-12-01

Tandem accelerator in Science Faculty, Kyoto University was renewed from 5 MV in the highest terminal voltage of Van de Graaff to 8 MV of Peletron in 1992. And, AMS effective for cosmic ray, dating, environment measurement and so forth is determined to a column of collaborative studies by universities and institutes in Japan. On this renewal, because of using high energy beam transportation of the present tandem accelerator, super high sensitivity measurement of long half-life radioactive isotopes of heavy elements such as {sup 36}Cl, {sup 41}Ca, {sup 129}I and so forth is aimed, although having some limitations due to small magnet. The accelerator is active in characteristics of the middle size tandem accelerator, and developing {sup 14}C measurement for its standard technology, as aiming at {sup 36}Cl measurement, at first. As a result, in this tandem accelerator stable and high beam transmittance could be obtained by adding a slit at negative ion source to make emittance of incident beam smaller. {sup 14}C/{sup 12}C ratio of Modan`s sample obtained by graphitizing NBS oxalic acid and Ded`s sample consisting of mineral graphite produced in Sri Lanka are measured to confirm better reproductivity of this system. Future development of successive incident method is planned to test actual carbon samples. (G.K.)

Multiple analyte adduct formation in liquid chromatography-tandem mass spectrometry - Advantages and limitations in the analysis of biologically-related samples.

Science.gov (United States)

Dziadosz, Marek

2018-05-01

Multiple analyte adduct formation was examined and discussed in the context of reproducible signal detection in liquid chromatography-tandem mass spectrometry applied in the analysis of biologically-related samples. Appropriate infusion solutions were prepared in H 2 O/methanol (3/97, v/v) with 1 mM sodium acetate and 10 mM acetic acid. An API 4000 QTrap tandem mass spectrometer was used for experiments performed in the negative scan mode (-Q1 MS) and the negative enhanced product ion mode (-EPI). γ‑Hydroxybutyrate and its deuterated form were used as model compounds to highlight both the complexity of adduct formation in popular mobile phases used and the effective signal compensation by the application of isotope-labelled analytes as internal standards. Copyright © 2018 Elsevier B.V. All rights reserved.

Quantitative, multiplexed workflow for deep analysis of human blood plasma and biomarker discovery by mass spectrometry.

Science.gov (United States)

Keshishian, Hasmik; Burgess, Michael W; Specht, Harrison; Wallace, Luke; Clauser, Karl R; Gillette, Michael A; Carr, Steven A

2017-08-01

Proteomic characterization of blood plasma is of central importance to clinical proteomics and particularly to biomarker discovery studies. The vast dynamic range and high complexity of the plasma proteome have, however, proven to be serious challenges and have often led to unacceptable tradeoffs between depth of coverage and sample throughput. We present an optimized sample-processing pipeline for analysis of the human plasma proteome that provides greatly increased depth of detection, improved quantitative precision and much higher sample analysis throughput as compared with prior methods. The process includes abundant protein depletion, isobaric labeling at the peptide level for multiplexed relative quantification and ultra-high-performance liquid chromatography coupled to accurate-mass, high-resolution tandem mass spectrometry analysis of peptides fractionated off-line by basic pH reversed-phase (bRP) chromatography. The overall reproducibility of the process, including immunoaffinity depletion, is high, with a process replicate coefficient of variation (CV) of 4,500 proteins are detected and quantified per patient sample on average, with two or more peptides per protein and starting from as little as 200 μl of plasma. The approach can be multiplexed up to 10-plex using tandem mass tags (TMT) reagents, further increasing throughput, albeit with some decrease in the number of proteins quantified. In addition, we provide a rapid protocol for analysis of nonfractionated depleted plasma samples analyzed in 10-plex. This provides ∼600 quantified proteins for each of the ten samples in ∼5 h of instrument time.

Complete Analysis of a Biologically Active Tetrapeptide: A Project Utilizing Thin-Layer Chromatography and Tandem Quadrupole Mass Spectrometry

Science.gov (United States)

Lefevre, Joseph W.; Dodsworth, David W.

2000-04-01

The biologically active tetrapeptide d-Ala-Gly-l-Phe-d-Leu ([des-Tyr1-d-Ala2-d-Leu5]enkephalin) was analyzed for its amino acid content and stereochemistry by normal and reversed-phase thin-layer chromatography (TLC), and its sequence was determined by tandem quadrupole mass spectrometry. The project involved sequential N-dansylation of a portion of the tetrapeptide, hydrolysis, isolation, and identification of the N-terminal amino acid as dansyl-alanine by comparison with standards using normal-phase TLC. A second portion of the tetrapeptide was hydrolyzed and the resulting four free amino acids were converted to their corresponding dansyl derivatives and purified by preparative normal-phase TLC. The three dansyl amino acids not identified previously were identified by TLC. The stereochemistry of each was determined by comparison with dansyl-dl-amino acid standards using reversed-phase TLC in the presence of ß-cyclodextrin, a chiral mobile phase additive. Finally, the correct amino acid sequence was determined by tandem quadrupole mass spectrometry. This project gives students valuable experience in microscale synthesis, both normal and reversed-phase TLC, stereochemical analysis, and mass spectrometry.

delta. -isobars and photodisintegration at intermediate energies

Energy Technology Data Exchange (ETDEWEB)

Suzumura, Jun-ichi; Futami, Yasuhiko [Science Univ. of Tokyo, Noda, Chiba (Japan). Faculty of Science and Technology

1982-12-01

The dynamics of the peak considered to be due to the two-nucleon process in the reaction /sup 9/Be(gamma, p) anything is investigated with the quasi-deuteron model. We show that the process is dominated by a two-nucleon mechanism with pion and rho-meson exchange through virtual delta-isobar formation (author).

Isobar contributions to the NN interaction

International Nuclear Information System (INIS)

Bagnoud, X.; Holinde, K.; Machleidt, R.

1981-01-01

The fourth-order noniterative 2π-exchange diagrams involving double-isobar intermediate states are evaluated in momentum space, in the framework of noncovariant perturbation theory. The role of these diagrams is studied by making a detailed comparison with (i) the corresponding iterative diagrams and (ii) diagrams involving NN or NΔ intermediate states. Current prescriptions for replacing all time-orderings of those diagrams by (simple) pion-range transition potentials are tested

Atmospheric Pressure Photoionization Tandem Mass Spectrometry of Androgens in Prostate Cancer

Science.gov (United States)

Lih, Fred Bjørn; Titus, Mark A.; Mohler, James L.; Tomer, Kenneth B.

2010-01-01

Androgen deprivation therapy is the most common treatment option for advanced prostate cancer. Almost all prostate cancers recur during androgen deprivation therapy, and new evidence suggests that androgen receptor activation persists despite castrate levels of circulating androgens. Quantitation of tissue levels of androgens is critical to understanding the mechanism of recurrence of prostate cancer during androgen deprivation therapy. A liquid chromatography atmospheric pressure photoionization tandem mass spectrometric method was developed for quantitation of tissue levels of androgens. Quantitation of the saturated keto-steroids dihydrotestosterone and 5-α-androstanedione required detection of a novel parent ion, [M + 15]+. The nature of this parent ion was explored and the method applied to prostate tissue and cell culture with comparison to results achieved using electrospray ionization. PMID:20560527

A new HF-resistant tandem spray chamber for improved determination of trace elements and Pb isotopes using inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Krachler, Michael; Rausch, Nicole; Feuerbacher, Helmut; Klemens, Patrick

2005-01-01

The use of a new HF-resistant tandem spray chamber arrangement consisting of a cyclonic spray chamber and a Scott-type spray chamber made from PFA and PEEK provides a straightforward approach for improving the performance of inductively coupled-mass spectrometry (ICP-MS). The characteristics of the tandem spray chamber were critically evaluated against a PEEK cyclonic and a PFA Scott-type spray chamber, respectively. Sensitivity across the entire mass range was increased by about three times compared to the conventional setup utilizing only one spray chamber. Precision of the results, especially at low signal intensities, improved by 160% and 31% compared to the cyclonic and Scott-type spray chamber, respectively. Using the tandem spray chamber, the oxide formation rate was lowered by about 50%. Signals as low as 30 counts could be determined under routine measurement conditions with a RSD of 2.4% thus allowing to precisely quantify small concentration differences at the ng l -1 concentration level. The excellent precision (0.02-0.07%) of 206 Pb / 207 Pb and 206 Pb / 208 Pb ratios determined in pore water samples was rather limited by the instrumental capabilities of the single collector ICP-MS instrument than by the performance of the tandem spray chamber

Intrathecal isobaric versus hyperbaric bupivacaine for elective caesarean section

International Nuclear Information System (INIS)

Aftab, S.; Ali, H.; Zafar, S.; Sheikh, M.; Sultan, T.

2007-01-01

To compare the results of isobaric bupivacaine (0.5%) with hyperbaric bupivacaine (0.75%) in cases of elective Caesarean Section, in respect of time to sensory analgesia, highest level of sensory block, haemodynamic effects, and complications. Sixty pregnant patients scheduled for elective Caesarean Section. The patients were randomly assigned to receive either 0.5% isobaric bupivacaine (Group-1B) or 0.75% hyperbaric bupivacaine (Group-HB) via intrathecal route. The time of onset of block, highest level of sensory block, cardio-respiratory data, duration of analgesia and complications were recorded during surgery. The time taken to reach T4 sensory analgesia in Group-1B was 6+-6.43 minutes as compared to 6.93+-7.8 minutes in Group-HB, while the highest sensory level achieved in Group-1B was T1 and in Group-HB T2. The lowest systolic blood pressure recorded in Group-1B was 83.27+-12.69 mmHg and in Group-HB 114.33+-13.83 mm Hg, the difference being significant (p<0.05). There was a higher incidence of complications in Group-1B as compared to Group-HB like high spinal analgesia, vomiting and discomfort. Intrathecal block showed a greater reduction in the systolic blood pressure, and associated complications, with Isobaric Bupivacaine as compared to Hyperbaric Bupivacaine. (author)

Isothermal-isobaric Nose-Hoover method application: correlation length and disclinations per particle

International Nuclear Information System (INIS)

Morales, J.J.; Nuevo, J.M.; Rull, L.F.

1987-01-01

The new isothermic-isobaric MD(T,p,N) method of Nose and Hoover is applied in Molecular Dynamics simulations to both liquid and solid near the phase transition. We tested for an appropriate value of the isobaric friction coefficient before calculating the correlation length in the liquid and the disclinations per particle in solid on a big system of 2304 particles. The results are compared with those obtained by traditional MD simulation (E,V,N). (author)

Specific determination of 20 primary aromatic amines in aqueous food simulants by liquid chromatography-electrospray ionization-tandem mass spectrometry

DEFF Research Database (Denmark)

Mortensen, Sarah Kelly; Trier, Xenia Thorsager; Foverskov, Annie

2005-01-01

A multi-analyte method without any pre-treatment steps using reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed and applied for the determination of 20 primary aromatic amines (PAA) associated with polyurethane (PUR) products or azo...

Determination of clarithromycin in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Jiang, Yao; Wang, Jiang; Li, Hao; Wang, Yingwu; Gu, Jingkai

2007-03-12

A rapid and sensitive method has been developed for the determination of clarithromycin in human plasma with liquid chromatography-tandem mass spectrometry. Clarithromycin and the internal standard, telmisartan were precipitated from the matrix (50 microl) with 200 microl acetonitrile and separated by HPLC using formic acid:10 mM ammonium acetate:methanol (1:99:400, v/v/v) as the mobile phase. The assay based on detection by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring mode was finished within 2.4 min. Linearity was over the concentration range 10-5000 ng/ml with a limit of detection of 0.50 ng/ml. Intra- and inter-day precision measured as relative standard deviation were bioequivalence study of two tablet formulations of clarithromycin.

PECAN: library-free peptide detection for data-independent acquisition tandem mass spectrometry data

Energy Technology Data Exchange (ETDEWEB)

Ting, Ying S.; Egertson, Jarrett D.; Bollinger, James G.; Searle, Brian C.; Payne, Samuel H.; Noble, William Stafford; MacCoss, Michael J.

2017-08-07

Data-independent acquisition (DIA) is an emerging mass spectrometry (MS)-based technique for unbiased and reproducible measurement of protein mixtures. DIA tandem mass spectrometry spectra are often highly multiplexed, containing product ions from multiple cofragmenting precursors. Detecting peptides directly from DIA data is therefore challenging; most DIA data analyses require spectral libraries. Here we present PECECAN (http://pecan.maccosslab.org), a library-free, peptide-centric tool that robustly and accurately detects peptides directly from DIA data. PECECAN reports evidence of detection based on product ion scoring, which enables detection of low-abundance analytes with poor precursor ion signal. We demonstrate the chromatographic peak picking accuracy and peptide detection capability of PECECAN, and we further validate its detection with data-dependent acquisition and targeted analyses. Lastly, we used PECECAN to build a plasma proteome library from DIA data and to query known sequence variants.

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)

On the chemical resolution of the {sup 87}Rb{sup +} (s{sup 0})/{sup 87}Sr{sup +} (s{sup 1}) isobaric interference: A kinetic search for an optimum reagent

Energy Technology Data Exchange (ETDEWEB)

Cheng Ping; Koyanagi, Gregory K. [Department of Chemistry, Centre for Research in Mass Spectrometry and Centre for Research in Earth and Space Science, York University, Toronto, Ontario, M3J 1P3 (Canada); Bohme, Diethard K. [Department of Chemistry, Centre for Research in Mass Spectrometry and Centre for Research in Earth and Space Science, York University, Toronto, Ontario, M3J 1P3 (Canada)], E-mail: dkbohme@yorku.ca

2008-10-03

Room-temperature reactions of the atomic cations Sr{sup +} and Rb{sup +} have been surveyed systematically with a variety of gases using an Inductively-Coupled Plasma/Selected-Ion Flow Tube (ICP/SIFT) tandem mass spectrometer. Rate coefficients and product distributions have been measured in He buffer gas at 0.35 Torr and 295 K for reactions of Sr{sup +} and Rb{sup +} with CH{sub 3}F, CH{sub 3}Cl, N{sub 2}O, CO{sub 2}, CS{sub 2}, SF{sub 6}, D{sub 2}O and NH{sub 3}. Rb{sup +} (s{sup 0}) is seen to be quite inert with these molecules and reacts either slowly by molecule addition or not at all, while Sr{sup +} (s{sup 1}) is much more reactive with all these 8 molecules, especially with CH{sub 3}F, CH{sub 3}Cl, N{sub 2}O and SF{sub 6}. Sr{sup +} reacts with CH{sub 3}F and SF{sub 6} by F-atom transfer, with CH{sub 3}Cl by Cl-atom transfer and with N{sub 2}O by O-atom transfer, and the reaction rate coefficients are all quite high, k {>=} 1.4 x 10{sup -11} cm{sup 3} molecules{sup -1} s{sup -1}. The extreme differences in reactivity with CH{sub 3}F, SF{sub 6}, CH{sub 3}Cl and N{sub 2}O provide a chemical basis for the separation of isobaric interferences of {sup 87}Rb{sup +} and {sup 87}Sr{sup +} often encountered in ICP-MS. Among these four molecules, SF{sub 6} exhibits the largest difference in reactivity, almost a factor of 10{sup 4}, and so is identified as the kinetically recommended reagent for the chemical resolution of the isobaric interference of {sup 87}Rb{sup +} and {sup 87}Sr{sup +}.

Generic solid phase extraction-liquid chromatography-tandem mass spectrometry method for fast determination of drugs in biological fluids

NARCIS (Netherlands)

Schellen, A.; Ooms, B.; Lagemaat, D. van de; Vreeken, R.; Dongen, W.D. van

2003-01-01

A generic method was developed for the fast determination of a wide range of drugs in serum or plasma. The methodology comprises generic solid-phase extraction, on-line coupled to gradient HPLC with tandem mass spectrometric detection (SPE-LC-MS/MS). The individual components of the SPE-LC-MS/MS

Isocratic Solid Phase Extraction-Liquid Chromatography (SPE-LC) Interfaced to High-Performance Tandem Mass Spectrometry for Rapid Protein Identification

DEFF Research Database (Denmark)

Hørning, Ole B; Kjeldsen, Frank; Theodorsen, Søren

2008-01-01

the isocratic solid phase extraction-liquid chromatography (SPE-LC) technology for rapid separation ( approximately 8 min) of simple peptide samples. We now extend these studies to demonstrate the potential of SPE-LC separation in combination with a hybrid linear ion trap-Orbitrap tandem mass spectrometer...

Dataset and standard operating procedure for newborn screening of six lysosomal storage diseases: By tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Susan Elliott

2016-09-01

Full Text Available In this data article we provide a detailed standard operating procedure for performing a tandem mass spectrometry, multiplex assay of 6 lysosomal enzymes for newborn screening of the lysosomal storage diseases Mucopolysaccharidosis-I, Pompe, Fabry, Niemann-Pick-A/B, Gaucher, and Krabbe, (Elliott, et al., 2016 [1]. We also provide the mass spectrometry peak areas for the product and internal standard ions typically observed with a dried blood spot punch from a random newborn, and we provide the daily variation of the daily mean activities for all 6 enzymes.

Quantification of urinary 0,0'-dityrosine, a biomarker for oxidative damage to proteins, by high performance liquid chromatography with triple quadrupole tandem mas spectrometry. A comparison with ion-trap tandem mass spectrometry.

NARCIS (Netherlands)

Orhan, H.; Coolen, S.; Meerman, J.H.N.

2005-01-01

We recently described an isotope dilution reversed-phase liquid chromatography-atmospheric pressure chemical ionization-ion-trap-tandem mass spectrometry (HPLC-APCI-MS/MS) method for the quantitative determination of oxidized amino acids in human urine, including o,o′-dityrosine, a specific marker

Tandem mass spectrometry: analysis of complex mixtures

International Nuclear Information System (INIS)

Singleton, K.E.

1985-01-01

Applications of tandem mass spectrometry (MS/MS) for the analysis of complex mixtures results in increased specificity and selectivity by using a variety of reagent gases in both negative and positive ion modes. Natural isotopic abundance ratios were examined in both simple and complex mixtures using parent, daughter and neutral loss scans. MS/MS was also used to discover new compounds. Daughter scans were used to identify seven new alkaloids in a cactus species. Three of these alkaloids were novel compounds, and included the first simple, fully aromatic isoquinoline alkaloids reported in Cactaceae. MS/MS was used to characterize the chemical reaction products of coal in studies designed to probe its macromolecular structure. Negative ion chemical ionization was utilized to study reaction products resulting from the oxidation of coal. Possible structural units in the precursor coal were predicted based on the reaction products identified, aliphatic and aromatic acids and their anhydrides. The MS/MS method was also used to characterize reaction products resulting from coal liquefaction and/or extraction. These studies illustrate the types of problems for which MS/MS is useful. Emphasis has been placed on characterization of complex mixtures by selecting experimental parameters which enhance the information obtained. The value of using MS/MS in conjunction with other analytical techniques as well as the chemical pretreatment is demonstrated

On Comparison of SimTandem with State-of-the-Art Peptide Identification Tools, Efficiency of Precursor Mass Filter and Dealing with Variable Modifications

Directory of Open Access Journals (Sweden)

Novák Jiří

2013-12-01

Full Text Available The similarity search in theoretical mass spectra generated from protein sequence databases is a widely accepted approach for identification of peptides from query mass spectra produced by shotgun proteomics. Growing protein sequence databases and noisy query spectra demand database indexing techniques and better similarity measures for the comparison of theoretical spectra against query spectra. We employ a modification of previously proposed parameterized Hausdorff distance for comparisons of mass spectra. The new distance outperforms the original distance, the angle distance and state-of-the-art peptide identification tools OMSSA and X!Tandem in the number of identified peptides even though the q-value is only 0.001. When a precursor mass filter is used as a database indexing technique, our method outperforms OMSSA in the speed of search. When variable modifications are not searched, the search time is similar to X!Tandem. We show that the precursor mass filter is an efficient database indexing technique for high-accuracy data even though many variable modifications are being searched. We demonstrate that the number of identified peptides is bigger when variable modifications are searched separately by more search runs of a peptide identification engine. Otherwise, the false discovery rates are affected by mixing unmodified and modified spectra together resulting in a lower number of identified peptides. Our method is implemented in the freely available application SimTandem which can be used in the framework TOPP based on OpenMS.

Prospective diagnosis of 2-methylbutyryl-CoA dehydrogenase deficiency in the Hmong population by newborn screening using tandem mass spectrometry

DEFF Research Database (Denmark)

Matern, Dietrich; He, Miao; Berry, Susan A

2003-01-01

but asymptomatic. METHODS: We report 8 additional patients identified by prospective newborn screening using tandem mass spectrometry. RESULTS: Molecular genetic analysis performed for 3 of these patients revealed that all are homozygous for an 1165A>G mutation that causes skipping of exon 10 of the SBCAD gene....... Although there was no obvious consanguinity, all patients belong to the Hmong, an ancient ethnic group that originated in China and constitutes only 0.8% and 0.6% of the Minnesota and Wisconsin population, respectively. Dietary treatment was initiated in the neonatal period. Except for 1 patient who...... developed mild muscle hypotonia, all patients remain asymptomatic at ages ranging from 3 to 14 months of age. CONCLUSIONS: These cases suggest that SBCAD deficiency is another inborn error of metabolism detectable by newborn screening using tandem mass spectrometry. The continued efficacy of long...

On the isobaric spin and the scattering matrix

International Nuclear Information System (INIS)

Hategan, Cornel

2002-01-01

The isobaric spin and the scattering matrix are fundamental nuclear physics concepts invented by Werner Heisenberg. The cardinal impact of the Heisenberg concepts on historical developpement of nuclear physics and other quantum and classical physics branches is discussed in this communication. Heisenberg in physics is synonymous to monumental scientific creations, namely: -'Creation of quantum mechanics' (Nobel Prize, 1932), -'Heisenberg relations', or 'Heisenberg inequalities' or 'Uncertainty principle' or 'Indeterminacy principle', - Basis for Copenhagen interpretation of Quantum Mechanics, -'world formula', - Project for a unitary theory representing all existing particles. Heisenberg does signify also important/cardinal contributions to many fields of physics as follows: - hydrodynamical theory of turbulence, (Dissertation, Sommerfeld); - theory of ferromagnetism; - study of cosmic rays; - nuclear physics. Heisenberg has invented two nuclear physics concepts, isobaric spin and scattering matrix which became cornerstones of the two main fields of the nuclear theory, namely, the nuclear structure (nuclear spectroscopy) and the nuclear reactions. This communication intends to illustrate the impact of the Heisenberg concepts on developpement of nuclear physics. (author)

Simultaneous drug identification in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

Science.gov (United States)

Lee, Hei Hwa; Chen, Suen Chi; Lee, Jong Feng; Lin, Hsin Yu; Chen, Bai Hsiun

2018-01-01

According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid-liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid comparison of diacetylmorphine on banknotes by tandem mass spectrometry.

Science.gov (United States)

Ebejer, Karl A; Brereton, Richard G; Carter, James F; Ollerton, Samantha L; Sleeman, Richard

2005-01-01

A procedure is described for the determination of the distribution of the contamination of banknotes with controlled drugs using tandem mass spectrometry. The method is illustrated using diacetylmorphine, which is the major active component of heroin. A series of banknotes is introduced into the mass spectrometer and the intensities of two product ions (m/z 328 and 268) derived from the precursor protonated molecule (m/z 370) are recorded. A banknote is considered contaminated if it shows a significant peak for both product ions, and if the ratio of intensities of these two peaks falls within accepted limits. The distribution of diacetylmorphine on sterling banknotes taken from general circulation within the UK can be modelled by an arcsin (square root) transformation of the data or by a log transformation of the data with a higher proportion of contamination. The two models were found to be in close agreement, predicting an upper limit (at 99.9% confidence) of contamination on banknotes from general circulation between 9 and 10%. The percentage contamination in a case study was calculated and compared to the background distribution using the two models proposed. This comparison revealed that the contamination present in the case study was inconsistent with that present on banknotes in general circulation. (c) 2005 John Wiley & Sons, Ltd.

Concise nuclear isobar charts

Energy Technology Data Exchange (ETDEWEB)

Bucka, H.

1986-01-01

In the Concise Nuclear Isobar Charts, data on binding energies of protons and neutrons in the ground state and excitation energies for low-lying nuclear energy levels are displayed, both of which are of great interest for transition processes as well as for questions of nuclear structure. Also, quantum numbers for angular momentum and parity are shown for these energy levels. For the stable nuclei, data for the relative abundances, and for unstable nucleon configurations, the transition probabilities are included in the data displayed. Due to the representation chosen for the atomic nuclei, in many cases a very clear first survey of systematic properties of nuclear energy states as well as spontaneous decay processes is achieved.

Method development for the determination of 24S-hydroxycholesterol in human plasma without derivatization by high-performance liquid chromatography with tandem mass spectrometry in atmospheric pressure chemical ionization mode.

Science.gov (United States)

Sugimoto, Hiroshi; Kakehi, Masaaki; Satomi, Yoshinori; Kamiguchi, Hidenori; Jinno, Fumihiro

2015-10-01

We developed a highly sensitive and specific high-performance liquid chromatography with tandem mass spectrometry method with an atmospheric pressure chemical ionization interface to determine 24S-hydroxycholesterol, a major metabolite of cholesterol formed by cytochrome P450 family 46A1, in human plasma without any derivatization step. Phosphate buffered saline including 1% Tween 80 was used as the surrogate matrix for preparation of calibration curves and quality control samples. The saponification process to convert esterified 24S-hydroxycholesterol to free sterols was optimized, followed by liquid-liquid extraction using hexane. Chromatographic separation of 24S-hydroxycholesterol from other isobaric endogenous oxysterols was successfully achieved with gradient mobile phase comprised of 0.1% propionic acid and acetonitrile using L-column2 ODS (2 μm, 2.1 mm id × 150 mm). This assay was capable of determining 24S-hydroxycholesterol in human plasma (200 μL) ranging from 1 to 100 ng/mL with acceptable intra- and inter-day precision and accuracy. The potential risk of in vitro formation of 24S-hydroxycholesterol by oxidation from endogenous cholesterol in human plasma was found to be negligible. The stability of 24S-hydroxycholesterol in relevant solvents and human plasma was confirmed. This method was successfully applied to quantify the plasma concentrations of 24S-hydroxycholesterol in male and female volunteers. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peptides derivatized with bicyclic quaternary ammonium ionization tags. Sequencing via tandem mass spectrometry.

Science.gov (United States)

Setner, Bartosz; Rudowska, Magdalena; Klem, Ewelina; Cebrat, Marek; Szewczuk, Zbigniew

2014-10-01

Improving the sensitivity of detection and fragmentation of peptides to provide reliable sequencing of peptides is an important goal of mass spectrometric analysis. Peptides derivatized by bicyclic quaternary ammonium ionization tags: 1-azabicyclo[2.2.2]octane (ABCO) or 1,4-diazabicyclo[2.2.2]octane (DABCO), are characterized by an increased detection sensitivity in electrospray ionization mass spectrometry (ESI-MS) and longer retention times on the reverse-phase (RP) chromatography columns. The improvement of the detection limit was observed even for peptides dissolved in 10 mM NaCl. Collision-induced dissociation tandem mass spectrometry of quaternary ammonium salts derivatives of peptides showed dominant a- and b-type ions, allowing facile sequencing of peptides. The bicyclic ionization tags are stable in collision-induced dissociation experiments, and the resulted fragmentation pattern is not significantly influenced by either acidic or basic amino acid residues in the peptide sequence. Obtained results indicate the general usefulness of the bicyclic quaternary ammonium ionization tags for ESI-MS/MS sequencing of peptides. Copyright © 2014 John Wiley & Sons, Ltd.

Sensitive measurement of serum 1α,25-dihydroxyvitamin D by liquid chromatography/tandem mass spectrometry after removing interference with immunoaffinity extraction.

Science.gov (United States)

Yuan, Chao; Kosewick, Justin; He, Xiang; Kozak, Marta; Wang, Sihe

2011-05-15

Vitamin D plays important roles in bone health and a variety of other pathophysiological conditions. 1α,25-Dihydroxyvitamin D is the active form of vitamin D. Quantification of serum 1α,25-dihydroxyvitamin D is useful for evaluation of several diseases including chronic renal failure, hypoparathyroidism, sarcoidosis, and rickets. Measurement of 1α,25-dihydroxyvitamin D is very challenging due to its low circulating concentration and presence of interfering substances in serum. In this report, a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for quantifying serum 1α,25-dihydroxyvitamin D is described. Lithium adducts of 1α,25-dihydroxyvitamin D were formed prior to mass spectrometry analysis to improve ionization efficiency. We tested a number of different sample preparation procedures and found that immunoaffinity extraction was the method of choice because it completely removed isobaric interferences and matrix effects present in patient serum. Extraction efficiency, expressed as absolute recovery, was greater than 60% in both patient serum and charcoal-stripped serum. This method was linear from 3.4 to 206.2 pg/mL for 1α,25-dihydroxyvitamin D(3) and 3.9 to 212.6 pg/mL for 1α,25-dihydroxyvitamin D(2) with an accuracy of 89.8-98.4% and 97.5-115.7%, respectively. Inter-assay and intra-assay coefficients of variance (CVs) for both analytes at two different concentration levels ranged from 2.5-7.0%. Comparison with a radioimmunoassay for measuring total 1α,25-dihydroxyvitamin D concentration using 40 patient samples showed a Deming regression slope of 0.751, a y-intercept of 0.84 pg/mL, an r value of 0.7909, and a mean percentage difference of -27.1%. Comparison with a reference LC/MS/MS method (n = 20) showed a Deming regression slope of 1.020, a y-intercept of 1.32 pg/mL, an r value of 0.9797, and a mean percentage difference of -2.9%. In conclusion, usage of immunoaffinity extraction enabled a sensitive LC/MS/MS method for

Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Gerssen, A.; McElhinney, M.; Mulder, P.P.J.; Bire, R.; Hess, P.; Boer, de J.

2009-01-01

The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC¿MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Gerssen, A.; McElhinney, A. M.; Mulder, P.P.J.; Bire, L.; Hess, P.; de Boer, J.

2009-01-01

The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

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

NARCIS (Netherlands)

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

2011-01-01

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

Variations in IBD (ACAD8) in children with elevated C4-carnitine detected by tandem mass spectrometry newborn screening

DEFF Research Database (Denmark)

Pedersen, Christina B; Bischoff, Claus; Christensen, Ernst

2006-01-01

or compound heterozygous for variations in the IBD gene have been reported. We present IBD deficiency in an additional four newborns with elevated C(4)-carnitine identified by tandem mass spectrometry (MS/MS) screening in Denmark and the United States. Three showed urinary excretions of isobutyryl...

Liquid chromatography-tandem mass spectrometry assay for the quantification of free and total sialic acid in human cerebrospinal fluid.

NARCIS (Netherlands)

Ham, M. van der; Koning, T.J. de; Lefeber, D.J.; Fleer, A.; Prinsen, B.H.; Sain-van der Velden, M.G. de

2010-01-01

BACKGROUND: Analysis of sialic acid (SA) metabolites in cerebrospinal fluid (CSF) is important for clinical diagnosis. In the present study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS) method for free sialic acid (FSA) and total sialic acid (TSA) in human CSF was

Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Dron, J.; El Haddad, I.; Temime-Roussel, B.; Wortham, H.; Marchand, N. [Univ Aix Marseille, CNRS, Lab Chim Provence, Equipe Instrumentat and React Atmospher, UMR 6264, F-13331 Marseille 3 (France); Jaffrezo, J.L. [Univ Grenoble 1, CNRS, UMR 5183, Lab Glaciol and Geophys Environm, F-38402 St Martin Dheres (France)

2010-07-01

The functional group composition of various organic aerosols (OA) is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCIMS/MS). The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R' respectively) and precursor ion (nitro groups, R-NO{sub 2}) scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA) produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular) to 13.5% (o-xylene photooxidation) of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France) during a strong winter pollution event. The three functional groups under study account for a total functionalization rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60%. Finally, examples of functional

Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry

Directory of Open Access Journals (Sweden)

J. Dron

2010-08-01

Full Text Available The functional group composition of various organic aerosols (OA is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS. The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R´ respectively and precursor ion (nitro groups, R-NO₂ scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular to 13.5% (o-xylene photooxidation of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60

Liquid chromatography-tandem mass spectrometric assay for the T790M mutant EGFR inhibitor osimertinib (AZD9291) in human plasma

NARCIS (Netherlands)

Rood, Johannes J M; van Bussel, Mark T J; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

2016-01-01

A method for the quantitative analysis by ultra-performance liquid chromatography-tandem mass spectrometry of the highly selective irreversible covalent inhibitor of EGFR-TK, osimertinib in human plasma was developed and validated, using pazopanib as an internal standard. The validation was

Quantitative proteomic analysis of serum from pregnant women carrying a fetus with conotruncal heart defect using isobaric tags for relative and absolute quantitation (iTRAQ labeling.

Directory of Open Access Journals (Sweden)

Ying Zhang

Full Text Available To identify differentially expressed proteins from serum of pregnant women carrying a conotruncal heart defects (CTD fetus, using proteomic analysis.The study was conducted using a nested case-control design. The 5473 maternal serum samples were collected at 14-18 weeks of gestation. The serum from 9 pregnant women carrying a CTD fetus, 10 with another CHD (ACHD fetus, and 11 with a normal fetus were selected from the above samples, and analyzed by using isobaric tags for relative and absolute quantitation (iTRAQ coupled with two-dimensional liquid chromatography-tandem mass spectrometry(2D LC-MS/MS. The differentially expressed proteins identified by iTRAQ were further validated with Western blot.A total of 105 unique proteins present in the three groups were identified, and relative expression data were obtained for 92 of them with high confidence by employing the iTRAQ-based experiments. The downregulation of gelsolin in maternal serum of fetus with CTD was further verified by Western blot.The identification of differentially expressed protein gelsolin in the serum of the pregnant women carrying a CTD fetus by using proteomic technology may be able to serve as a foundation to further explore the biomarker for detection of CTD fetus from the maternal serum.

Multiresidue analysis of 47 pesticides in cooked wheat flour and polished rice by liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Lee, Sung Jung; Park, Hyeong Jin; Kim, Wooseong; Jin, Jong Sung; Abd El-Aty, A M; Shim, Jae-Han; Shin, Sung Chul

2009-04-01

Liquid chromatography in conjunction with tandem mass spectrometry was used to directly quantify of 47 pesticide residues from cooked wheat flour and polished rice, which are the most widely consumed cereals in the Republic of Korea. The sample clean-up was carried out according to the method established by the Korea Food and Drug Administration. The mobile phase for liquid chromatography separation consisted of water and 5 mm methanolic ammonium formate. Tandem mass spectroscopy experiments were performed in electrospray ionization positive mode and the multiple reaction monitoring mode. The matrix effects estimated for the 47 pesticides had a mean value of 99% and ranged from 45 to 147%. High recoveries (70-140%) and relative standard deviations (flour and polished rice samples. Of the screened pesticide residues, only tricyclazole and fenobucarb were found in polished rice samples. However, no samples contained residues above the MRL established by the Korea Food and Drug Administration.

Recent advances of liquid chromatography-(tandem) mass spectrometry in clinical and forensic toxicology.

Science.gov (United States)

Peters, Frank T

2011-01-01

Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) has become increasingly important in clinical and forensic toxicology as well as doping control and is now a robust and reliable technique for routine analysis in these fields. In recent years, methods for LC-MS(/MS)-based systematic toxicological analysis using triple quadrupole or ion trap instruments have been considerably improved and a new screening approach based on high-resolution MS analysis using benchtop time-of-flight MS instruments has been developed. Moreover, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in various biomatrices have been published. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2006. Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Rapid Determination of Imatinib in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study

Energy Technology Data Exchange (ETDEWEB)

Yang, Jeong Soo; Cho, Eun Gi; Huh, Wooseong; Ko, Jaewook; Jung, Jin Ah; Lee, Sooyoun [Samsung Medical Center, Seoul (Korea, Republic of)

2013-08-15

A simple, fast and robust analytical method was developed to determine imatinib in human plasma using liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode. Imatinib and labeled internal standard were extracted from plasma with a simple protein precipitation. The chromatographic separation was performed using an isocratic elution of mobile phase involving 5.0 mM ammonium formate in water -5.0 mM ammonium formate in methanol (30:70, v/v) over 3.0 min on reversed-stationary phase. The detection was performed using a triple-quadrupole tandem mass spectrometer in multiple-reaction monitoring mode. The developed method was validated with lower limit of quantification of 10 ng/mL. The calibration curve was linear over 10-2000 ng/mL (R{sup 2} > 0.99). The method validation parameters met the acceptance criteria. The spiked samples and standard solutions were stable under conditions for storage and handling. The reliable method was successfully applied to real sample analyses and thus a pharmacokinetic study in 27 healthy Korean male volunteers.

Structure of [M + H − H2O]+ from Protonated Tetraglycine Revealed by Tandem Mass Spectrometry and IRMPD Spectroscopy

NARCIS (Netherlands)

Bythell, B. J.; Dain, Ryan P.; Curtice, Stephanie S.; Oomens, Jos; Steill, Jeffrey D.; Groenewold, Gary S.; la Paizs, Bé; van Stipdonk, M. J.

2010-01-01

Multiple-stage tandem mass spectrometry and collision-induced dissociation were used to investigate loss of H2O or CH3OH from protonated versions of GGGX (where X = G, A, and V), GGGGG, and the methyl esters of these peptides. In addition, wavelength-selective infrared multiple photon dissociation

Clinical validation of cutoff target ranges in newborn screening of metabolic disorders by tandem mass spectrometry : A worldwide collaborative project

NARCIS (Netherlands)

McHugh, David M. S.; Cameron, Cynthia A.; Abdenur, Jose E.; Abdulrahman, Mahera; Adair, Ona; Al Nuaimi, Shahira Ahmed; Ahlman, Henrik; Allen, Jennifer J.; Antonozzi, Italo; Archer, Shaina; Au, Sylvia; Auray-Blais, Christiane; Baker, Mei; Bamforth, Fiona; Beckmann, Kinga; Pino, Gessi Bentz; Berberich, Stanton L.; Binard, Robert; Boemer, Francois; Bonham, Jim; Breen, Nancy N.; Bryant, Sandra C.; Caggana, Michele; Caldwell, S. Graham; Camilot, Marta; Campbell, Carlene; Carducci, Claudia; Cariappa, Rohit; Carlisle, Clover; Caruso, Ubaldo; Cassanello, Michela; Miren Castilla, Ane; Castineiras Ramos, Daisy E.; Chakraborty, Pranesh; Chandrasekar, Ram; Ramos, Alfredo Chardon; Cheillan, David; Chien, Yin-Hsiu; Childs, Thomas A.; Chrastina, Petr; Sica, Yuri Cleverthon; Cocho de Juan, Jose Angel; Elena Colandre, Maria; Cornejo Espinoza, Veronica; Corso, Gaetano; Currier, Robert; Cyr, Denis; Czuczy, Noemi; D'Apolito, Oceania; Davis, Tim; de Sain-Van der Velden, Monique G.; Delgado Pecellin, Carmen; Di Gangi, Iole Maria; Di Stefano, Cristina Maria; Dotsikas, Yannis; Downing, Melanie; Downs, Stephen M.; Dy, Bonifacio; Dymerski, Mark; Rueda, Inmaculada; Elvers, Bert; Eaton, Roger; Eckerd, Barbara M.; El Mougy, Fatma; Eroh, Sarah; Espada, Mercedes; Evans, Catherine; Fawbush, Sandy; Fijolek, Kristel F.; Fisher, Lawrence; Franzson, Leifur; Frazier, Dianne M.; Garcia, Luciana R. C.; Garcia-Valdecasas Bermejo, Maria Sierra; Gavrilov, Dimitar; Gerace, Rosemarie; Giordano, Giuseppe; Irazabal, Yolanda Gonzalez; Greed, Lawrence C.; Grier, Robert; Grycki, Elyse; Gu, Xuefan; Gulamali-Majid, Fizza; Hagar, Arthur F.; Han, Lianshu; Hannon, W. Harry; Haslip, Christa; Hassan, Fayza Abdelhamid; He, Miao; Hietala, Amy; Himstedt, Leslie; Hoffman, Gary L.; Hoffman, William; Hoggatt, Philis; Hopkins, Patrick V.; Hougaard, David M.; Hughes, Kerie; Hunt, Patricia R.; Hwu, Wuh-Liang; Hynes, June; Ibarra-Gonzalez, Isabel; Ingham, Cindy A.; Ivanova, Maria; Jacox, Ward B.; John, Catharine; Johnson, John P.; Jonsson, Jon J.; Karg, Eszter; Kasper, David; Klopper, Brenda; Katakouzinos, Dimitris; Khneisser, Issam; Knoll, Detlef; Kobayashi, Hirinori; Koneski, Ronald; Kozich, Viktor; Kouapei, Rasoul; Kohlmueller, Dirk; Kremensky, Ivo; la Marca, Giancarlo; Lavochkin, Marcia; Lee, Soo-Youn; Lehotay, Denis C.; Lemes, Aida; Lepage, Joyce; Lesko, Barbara; Lewis, Barry; Lim, Carol; Linard, Sharon; Lindner, Martin; Lloyd-Puryear, Michele A.; Lorey, Fred; Loukas, Yannis L.; Luedtke, Julie; Maffitt, Neil; Magee, J. Fergall; Manning, Adrienne; Manos, Shawn; Marie, Sandrine; Hadachi, Sonia Marchezi; Marquardt, Gregg; Martin, Stephen J.; Matern, Dietrich; Gibson, Stephanie K. Mayfield; Mayne, Philip; McCallister, Tonya D.; McCann, Mark; McClure, Julie; McGill, James J.; McKeever, Christine D.; McNeilly, Barbara; Morrissey, Mark A.; Moutsatsou, Paraskevi; Mulcahy, Eleanor A.; Nikoloudis, Dimitris; Norgaard-Pedersen, Bent; Oglesbee, Devin; Oltarzewski, Mariusz; Ombrone, Daniela; Ojodu, Jelili; Papakonstantinou, Vagelis; Reoyo, Sherly Pardo; Park, Hyung-Doo; Pasquali, Marzia; Pasquini, Elisabetta; Patel, Pallavi; Pass, Kenneth A.; Peterson, Colleen; Pettersen, Rolf D.; Pitt, James J.; Poh, Sherry; Pollak, Arnold; Porter, Cory; Poston, Philip A.; Price, Ricky W.; Queijo, Cecilia; Quesada, Jonessy; Randell, Edward; Ranieri, Enzo; Raymond, Kimiyo; Reddic, John E.; Reuben, Alejandra; Ricciardi, Charla; Rinaldo, Piero; Rivera, Jeff D.; Roberts, Alicia; Rocha, Hugo; Roche, Geraldine; Greenberg, Cheryl Rochman; Egea Mellado, Jose Maria; Jess Juan-Fita, Maria; Ruiz, Consuelo; Ruoppolo, Margherita; Rutledge, S. Lane; Ryu, Euijung; Saban, Christine; Sahai, Inderneel; Salazar Garcia-Blanco, Maria Isabel; Santiago-Borrero, Pedro; Schenone, Andrea; Schoos, Roland; Schweitzer, Barb; Scott, Patricia; Seashore, Margretta R.; Seeterlin, Mary A.; Sesser, David E.; Sevier, Darrin W.; Shone, Scott M.; Sinclair, Graham; Skrinska, Victor A.; Stanley, Eleanor L.; Strovel, Erin T.; Jones, April L. Studinski; Sunny, Sherlykutty; Takats, Zoltan; Tanyalcin, Tijen; Teofoli, Francesca; Thompson, J. Robert; Tomashitis, Kathy; Domingos, Mouseline Torquado; Torres, Jasmin; Torres, Rosario; Tortorelli, Silvia; Turi, Sandor; Turner, Kimberley; Tzanakos, Nick; Valiente, Alf G.; Vallance, Hillary; Vela-Amieva, Marcela; Vilarinho, Laura; von Doebeln, Ulrika; Vincent, Marie-Francoise; Vorster, B. Chris; Watson, Michael S.; Webster, Dianne; Weiss, Sheila; Wilcken, Bridget; Wiley, Veronica; Williams, Sharon K.; Willis, Sharon A.; Woontner, Michael; Wright, Katherine; Yahyaoui, Raquel; Yamaguchi, Seiji; Yssel, Melissa; Zakowicz, Wendy M.

Purpose: To achieve clinical validation of cutoff values for newborn screening by tandem mass spectrometry through a worldwide collaborative effort. Methods: Cumulative percentiles of amino acids and acylcarnitines in dried blood spots of approximately 25-30 million normal newborns and 10,742

Coulomb effects in isobaric cold fission from reactions 233U(nth,f), 235U(nth,f),239Pu(nth,f) and 252Cf(sf)

International Nuclear Information System (INIS)

Montoya, Modesto

2013-01-01

The Coulomb effect hypothesis, formerly used to interpret fluctuations in the curve of maximal total kinetic energy as a function of light fragment mass in reactions 233 U(n th ,f), 235 U(n th ,f) and 239 Pu(n th ,f), is confirmed in high kinetic energy as well as in low excitation energy windows, respectively. Data from reactions 233 U(n th ,f), 235 U(n th ,f), 239 Pu(n th ,f) and 252 Cf(sf) show that, between two isobaric fragmentations with similar Q-values, the more asymmetric charge split reaches the higher value of total kinetic energy. Moreover, in isobaric charge splits with different Q-values, similar preference for asymmetrical fragmentations is observed in low excitation energy windows. (author).

On pattern recognition of fireballs and isobars in the Lobachevsky velocity space

International Nuclear Information System (INIS)

Bubelev, E.G.

1977-01-01

It is shown that a multidimensional statistical analysis of high particle jets means the classification of invariant pictures for their kinematics into types (with the production of fireballs and isobars and without one or the other) and recognition of statistical patterms for fireballs and isobars in the Lobachevsky velocity space (invariant phase space in high energy physics). The concept of likeness (closeness) of single-type pictures is taken as basis for such a classification. Two known methods of formalizing this concept are generalized in application to the noneuclidean metric of the velocity space

The utility of ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) for clinically relevant steroid analysis.

Science.gov (United States)

Storbeck, Karl-Heinz; Gilligan, Lorna; Jenkinson, Carl; Baranowski, Elizabeth S; Quanson, Jonathan L; Arlt, Wiebke; Taylor, Angela E

2018-05-15

Liquid chromatography tandem mass spectrometry (LC-MS/MS) assays are considered the reference standard for serum steroid hormone analyses, while full urinary steroid profiles are only achievable by gas chromatography (GC-MS). Both LC-MS/MS and GC-MS have well documented strengths and limitations. Recently, commercial ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) systems have been developed. These systems combine the resolution of GC with the high-throughput capabilities of UHPLC. Uptake of this new technology into research and clinical labs has been slow, possibly due to the perceived increase in complexity. Here we therefore present fundamental principles of UHPSFC-MS/MS and the likely applications for this technology in the clinical research setting, while commenting on potential hurdles based on our experience to date. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Meson and isobar degrees of freedom in nuclear forces

International Nuclear Information System (INIS)

Vinh Mau, R.

1983-10-01

The current status of the low energy theory of the NN and NantiN interactions is reviewed, with special attention given to the role of the meson and isobar degrees of freedom. Phenomenology and fits to recent data are also described

Detection and identification of drugs and toxicants in human body fluids by liquid chromatography-tandem mass spectrometry under data-dependent acquisition control and automated database search.

Science.gov (United States)

Oberacher, Herbert; Schubert, Birthe; Libiseller, Kathrin; Schweissgut, Anna

2013-04-03

Systematic toxicological analysis (STA) is aimed at detecting and identifying all substances of toxicological relevance (i.e. drugs, drugs of abuse, poisons and/or their metabolites) in biological material. Particularly, gas chromatography-mass spectrometry (GC/MS) represents a competent and commonly applied screening and confirmation tool. Herein, we present an untargeted liquid chromatography-tandem mass spectrometry (LC/MS/MS) assay aimed to complement existing GC/MS screening for the detection and identification of drugs in blood, plasma and urine samples. Solid-phase extraction was accomplished on mixed-mode cartridges. LC was based on gradient elution in a miniaturized C18 column. High resolution electrospray ionization-MS/MS in positive ion mode with data-dependent acquisition control was used to generate tandem mass spectral information that enabled compound identification via automated library search in the "Wiley Registry of Tandem Mass Spectral Data, MSforID". Fitness of the developed LC/MS/MS method for application in STA in terms of selectivity, detection capability and reliability of identification (sensitivity/specificity) was demonstrated with blank samples, certified reference materials, proficiency test samples, and authentic casework samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Improving quantitative precision and throughput by reducing calibrator use in liquid chromatography-tandem mass spectrometry

International Nuclear Information System (INIS)

Rule, Geoffrey S.; Rockwood, Alan L.

2016-01-01

To improve efficiency in our mass spectrometry laboratories we have made efforts to reduce the number of calibration standards utilized for quantitation over time. We often analyze three or more batches of 96 samples per day, on a single instrument, for a number of assays. With a conventional calibration scheme at six concentration levels this amounts to more than 5000 calibration points per year. Modern LC-tandem mass spectrometric instrumentation is extremely rugged however, and isotopically labelled internal standards are widely available. This made us consider whether alternative calibration strategies could be utilized to reduce the number of calibration standards analyzed while still retaining high precision and accurate quantitation. Here we demonstrate how, by utilizing a single calibration point in each sample batch, and using the resulting response factor (RF) to update an existing, historical response factor (HRF), we are able to obtain improved precision over a conventional multipoint calibration approach, as judged by quality control samples. The laboratory component of this study was conducted with an existing LC tandem mass spectrometric method for three androgen analytes in our production laboratory. Using examples from both simulated and laboratory data we illustrate several aspects of our single point alternative calibration strategy and compare it with a conventional, multipoint calibration approach. We conclude that both the cost and burden of preparing multiple calibration standards with every batch of samples can be reduced while at the same time maintaining, or even improving, analytical quality. - Highlights: • Use of a weighted single point calibration approach improves quantitative precision. • A weighted response factor approach incorporates historical calibration information. • Several scenarios are discussed with regard to their influence on quantitation.

Improving quantitative precision and throughput by reducing calibrator use in liquid chromatography-tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Rule, Geoffrey S., E-mail: geoffrey.s.rule@aruplab.com [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Rockwood, Alan L. [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Department of Pathology, University of Utah School of Medicine, 2100 Jones Medical Research Bldg., Salt Lake City, UT 84132 (United States)

2016-05-05

To improve efficiency in our mass spectrometry laboratories we have made efforts to reduce the number of calibration standards utilized for quantitation over time. We often analyze three or more batches of 96 samples per day, on a single instrument, for a number of assays. With a conventional calibration scheme at six concentration levels this amounts to more than 5000 calibration points per year. Modern LC-tandem mass spectrometric instrumentation is extremely rugged however, and isotopically labelled internal standards are widely available. This made us consider whether alternative calibration strategies could be utilized to reduce the number of calibration standards analyzed while still retaining high precision and accurate quantitation. Here we demonstrate how, by utilizing a single calibration point in each sample batch, and using the resulting response factor (RF) to update an existing, historical response factor (HRF), we are able to obtain improved precision over a conventional multipoint calibration approach, as judged by quality control samples. The laboratory component of this study was conducted with an existing LC tandem mass spectrometric method for three androgen analytes in our production laboratory. Using examples from both simulated and laboratory data we illustrate several aspects of our single point alternative calibration strategy and compare it with a conventional, multipoint calibration approach. We conclude that both the cost and burden of preparing multiple calibration standards with every batch of samples can be reduced while at the same time maintaining, or even improving, analytical quality. - Highlights: • Use of a weighted single point calibration approach improves quantitative precision. • A weighted response factor approach incorporates historical calibration information. • Several scenarios are discussed with regard to their influence on quantitation.

Structural Characterisation of Acetogenins from Annona muricata by Supercritical Fluid Chromatography Coupled to High-Resolution Tandem Mass Spectrometry.

Science.gov (United States)

Laboureur, Laurent; Bonneau, Natacha; Champy, Pierre; Brunelle, Alain; Touboul, David

2017-11-01

Acetogenins are plant polyketides known to be cytotoxic and proposed as antitumor candidates. They are also suspected to be alimentary neurotoxins. Their occurrence as complex mixtures renders their dereplication and structural identification difficult using liquid chromatography coupled to tandem mass spectrometry and efforts are required to improve the methodology. To develop a supercritical fluid chromatography (SFC) high-resolution tandem mass spectrometry method, involving lithium post-column cationisation, for the structural characterisation of Annonaceous acetogenins in crude extracts. The seeds of Annona muricata L. were extracted with methanol. Supercritical fluid chromatography of the extract, using a 2-ethylpyridine stationary phase column, was monitored using a high-resolution quadrupole time-of-flight mass spectrometer. Lithium iodide was added post-column in the make-up solvent. For comparison, the same extract was analysed using high-pressure liquid chromatography coupled to the same mass spectrometer, with a column based on solid core particles. Sensitivity was similar for both HPLC and SFC approaches. Retention behaviour and fragmentation pathways of three different isomer groups are described. A previously unknown group of acetogenins was also evidenced for the first time. The use of SFC-MS/MS allows the reduction of the time of analysis, of environmental impact and an increase in the chromatographic resolution, compared to liquid chromatography. This new methodology enlightened a new group of acetogenins, isomers of montanacin-D. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Single atom counting with accelerators

Energy Technology Data Exchange (ETDEWEB)

Woelfli, W [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1984-02-01

Direct detection of radioisotopes with conventional mass spectrometers is possible when the potential background atoms, in particular stable isotopes of the same mass (isobars) or molecules of similar mass are present in sufficiently low concentrations. Most of the long lived radioisotopes of interest for dating purposes however, occur in such small concentrations that their peak in the mass spectrum is obscured by the stable isobar and molecule distributions. The key idea of the new AMS technique which allows us to measure directly such small concentrations is the acceleration of the sample atoms to MeV energies and to use various filter processes and particle identification techniques developed for nuclear physics research to eliminate the isobaric and molecular interferences. The detection methods used for each radioisotope depend on the dominant background atoms and these in turn depend on the specific accelerator used. The problems encountered in transforming an existing particle accelerator into a high precision dating tool are considerable and have been solved only recently for one type of accelerator, notably the tandem Van de Graaff. For this reason the description of the AMS method and some of its applications is restricted to this type of accelerator only.

Silver complexation and tandem mass spectrometry for differentiation of isomeric flavonoid diglycosides.

Science.gov (United States)

Zhang, Junmei; Brodbelt, Jennifer S

2005-03-15

For detection and differentiation of isomeric flavonoids, electrospray ionization mass spectrometry is used to generate silver complexes of the type (Ag + flavonoid)+. Collisionally activated dissociation (CAD) of the resulting 1:1 silver/flavonoid complexes allows isomer differentiation of flavonoids. Eighteen flavonoid diglycosides constituting seven isomeric series are distinguishable from each other based on the CAD patterns of their silver complexes. Characteristic dissociation pathways allow identification of the site of glycosylation, the type of disaccharide (rutinose versus neohesperidose), and the type of aglycon (flavonol versus flavone versus flavanone). This silver complexation method is more universal than previous metal complexation methods, as intense silver complexes are observed even for flavonoids that lack the typical metal chelation sites. To demonstrate the feasibility of using silver complexation and tandem mass spectrometry to characterize flavonoids in complex mixtures, flavonoids extracted from grapefruit juice are separated by high-performance liquid chromatography and analyzed via a postcolumn complexation ESI-MS/MS strategy. Diagnostic fragmentation pathways of the silver complexes of the individual eluting flavonoids allow successful identification of the six flavonoids in the extract.

Improved detection limit for {sup 59}Ni using the technique of accelerator mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Persson, Per; Erlandsson, Bengt; Hellborg, Ragnar; Kiisk, Madis; Larsson, Ragnar; Skog, Goeran; Stenstroem, Kristina [Lund Univ. (Sweden). Dept. of Nuclear Physics

2002-11-01

59 Ni is produced by neutron activation in the stainless steel close to the core of a nuclear reactor. To be able to classify the different parts of the reactor with respect to their content of long-lived radionuclides before final storage it is important to measure the 59 Ni level. Accelerator mass spectrometry is an ultra-sensitive method for counting atoms, suitable for 59 Ni measurements. Improvements in the reduction of the background and in the chemical reduction of cobalt, the interfering isobar, have been made. This chemical purification is essential when using small tandem accelerators, <3 MV, combined with the detection of characteristic projectile X-rays. These improvements have lowered the detection limit for 59 Ni by a factor of twenty compared with the first value reported for the Lund AMS facility. Material from the Swedish nuclear industry has been analysed and examples of the results are presented.

Mass Spectrometry Parameters Optimization for the 46 Multiclass Pesticides Determination in Strawberries with Gas Chromatography Ion-Trap Tandem Mass Spectrometry

Science.gov (United States)

Fernandes, Virgínia C.; Vera, Jose L.; Domingues, Valentina F.; Silva, Luís M. S.; Mateus, Nuno; Delerue-Matos, Cristina

2012-12-01

Multiclass analysis method was optimized in order to analyze pesticides traces by gas chromatography with ion-trap and tandem mass spectrometry (GC-MS/MS). The influence of some analytical parameters on pesticide signal response was explored. Five ion trap mass spectrometry (IT-MS) operating parameters, including isolation time (IT), excitation voltage (EV), excitation time (ET), maximum excitation energy or " q" value (q), and isolation mass window (IMW) were numerically tested in order to maximize the instrument analytical signal response. For this, multiple linear regression was used in data analysis to evaluate the influence of the five parameters on the analytical response in the ion trap mass spectrometer and to predict its response. The assessment of the five parameters based on the regression equations substantially increased the sensitivity of IT-MS/MS in the MS/MS mode. The results obtained show that for most of the pesticides, these parameters have a strong influence on both signal response and detection limit. Using the optimized method, a multiclass pesticide analysis was performed for 46 pesticides in a strawberry matrix. Levels higher than the limit established for strawberries by the European Union were found in some samples.

Mesonic and isobar degrees of freedom in nuclei

International Nuclear Information System (INIS)

Muether, H.

1978-01-01

A study is made in 16 O of the effects of mesonic and isobar degrees of freedom. Taking these degrees of freedom explicitly into account causes a change of the bare nucleon-nucleon (NN) interaction going from the description of the two-nucleon system (NN-scattering, deuteron) to the many-body system of complex nuclei. Three main effects are discussed: First, the mesonic degrees of freedom, taken into account in a noncovariant perturbation theory, introduce and additional density dependence into the NN interaction. In a Brueckner-Hartree-Fock calculation for 16 O this leads to an improvement of the radius with a small change of the energy. Second, fourth-order iterative diagrams involving NΔ-and ΔΔ-intermediate states give less medium range attraction in complex nuclei than a NN-potential which is also fitted to the NN-data but does not treat these terms explicitly. Third, effective three-N forces, caused by excitation of isobars, give rise to a small amount of attraction only. For 16 O the additional binding energy is only about 0.5 MeV per particle. (author)

Improving data quality and preserving HCD-generated reporter ions with EThcD for isobaric tag-based quantitative proteomics and proteome-wide PTM studies

International Nuclear Information System (INIS)

Yu, Qing; Shi, Xudong; Feng, Yu; Kent, K. Craig; Li, Lingjun

2017-01-01

Mass spectrometry (MS)-based isobaric labeling has undergone rapid development in recent years due to its capability for high throughput quantitation. Apart from its originally designed use with collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD), isobaric tagging technique could also work with electron-transfer dissociation (ETD), which provides complementarity to CID and is preferred in sequencing peptides with post-translational modifications (PTMs). However, ETD suffers from long reaction time, reduced duty cycle and bias against peptides with lower charge states. In addition, common fragmentation mechanism in ETD results in altered reporter ion production, decreased multiplexing capability, and even loss of quantitation capability for some of the isobaric tags, including custom-designed dimethyl leucine (DiLeu) tags. Here, we demonstrate a novel electron-transfer/higher-energy collision dissociation (EThcD) approach that preserves original reporter ion channels, mitigates bias against lower charge states, improves sensitivity, and significantly improves data quality for quantitative proteomics and proteome-wide PTM studies. Systematic optimization was performed to achieve a balance between data quality and sensitivity. We provide direct comparison of EThcD with ETD and HCD for DiLeu- and TMT-labeled HEK cell lysate and IMAC enriched phosphopeptides. Results demonstrate improved data quality and phosphorylation localization accuracy while preserving sufficient reporter ion production. Biological studies were performed to investigate phosphorylation changes in a mouse vascular smooth muscle cell line treated with four different conditions. Overall, EThcD exhibits superior performance compared to conventional ETD and offers distinct advantages compared to HCD in isobaric labeling based quantitative proteomics and quantitative PTM studies. - Highlights: • EThcD was optimized for isobaric tag-labeled peptides for quantitative

Improving data quality and preserving HCD-generated reporter ions with EThcD for isobaric tag-based quantitative proteomics and proteome-wide PTM studies

Energy Technology Data Exchange (ETDEWEB)

Yu, Qing [School of Pharmacy, University of Wisconsin, Madison, WI 53705 (United States); Shi, Xudong [Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705 (United States); Feng, Yu [School of Pharmacy, University of Wisconsin, Madison, WI 53705 (United States); Kent, K. Craig [Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705 (United States); Li, Lingjun, E-mail: lingjun.li@wisc.edu [School of Pharmacy, University of Wisconsin, Madison, WI 53705 (United States); Department of Chemistry, University of Wisconsin, Madison, WI 53706 (United States)

2017-05-22

Mass spectrometry (MS)-based isobaric labeling has undergone rapid development in recent years due to its capability for high throughput quantitation. Apart from its originally designed use with collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD), isobaric tagging technique could also work with electron-transfer dissociation (ETD), which provides complementarity to CID and is preferred in sequencing peptides with post-translational modifications (PTMs). However, ETD suffers from long reaction time, reduced duty cycle and bias against peptides with lower charge states. In addition, common fragmentation mechanism in ETD results in altered reporter ion production, decreased multiplexing capability, and even loss of quantitation capability for some of the isobaric tags, including custom-designed dimethyl leucine (DiLeu) tags. Here, we demonstrate a novel electron-transfer/higher-energy collision dissociation (EThcD) approach that preserves original reporter ion channels, mitigates bias against lower charge states, improves sensitivity, and significantly improves data quality for quantitative proteomics and proteome-wide PTM studies. Systematic optimization was performed to achieve a balance between data quality and sensitivity. We provide direct comparison of EThcD with ETD and HCD for DiLeu- and TMT-labeled HEK cell lysate and IMAC enriched phosphopeptides. Results demonstrate improved data quality and phosphorylation localization accuracy while preserving sufficient reporter ion production. Biological studies were performed to investigate phosphorylation changes in a mouse vascular smooth muscle cell line treated with four different conditions. Overall, EThcD exhibits superior performance compared to conventional ETD and offers distinct advantages compared to HCD in isobaric labeling based quantitative proteomics and quantitative PTM studies. - Highlights: • EThcD was optimized for isobaric tag-labeled peptides for quantitative

[Rapid determination of 8 urinary carbamate pesticides by liquid chromatography-tandem mass spectrometry].

Science.gov (United States)

Liu, Hualiang; Wang, Yuan; Zhu, Baoli

2015-11-01

To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides. After being purified by acetonitrile precipitation, urine samples were transferred to a liquid chromatography-tandem mass spectrometry system, and the concentrations of 8 carbamate pesticides were determined by external standard method. A C18 column was used for ultra-high-performance liquid chromatography; methanol/ammonium acetate solution was used as the mobile phase for gradient elution; the mass spectrometer was operated in a multi-reaction monitoring mode. The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 µg/L, and the recovery rates were 61.0%~121% at spiked levels of 20, 200 and 800 µg/L, with a relative standard deviation of 1.7%~5.5%. This determination method meets the Guide for establishing occupational health standards-part 5: Determination methods of chemicals in biological materials, and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.

Liquid chromatography-tandem mass spectrometric assay for the tyrosine kinase inhibitor afatinib in mouse plasma using salting-out liquid-liquid extraction

NARCIS (Netherlands)

Sparidans, Rolf W; van Hoppe, Stephanie; Rood, Johannes J M; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H

2016-01-01

A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for afatinib, an irreversible inhibitor of the ErbB (erythroblastic leukemia viral oncogene homolog) tyrosine kinase family, was developed and validated. Plasma samples were pre-treated using salting-out

Approaches towards the automated interpretation and prediction of electrospray tandem mass spectra of non-peptidic combinatorial compounds.

Science.gov (United States)

Klagkou, Katerina; Pullen, Frank; Harrison, Mark; Organ, Andy; Firth, Alistair; Langley, G John

2003-01-01

Combinatorial chemistry is widely used within the pharmaceutical industry as a means of rapid identification of potential drugs. With the growth of combinatorial libraries, mass spectrometry (MS) became the key analytical technique because of its speed of analysis, sensitivity, accuracy and ability to be coupled with other analytical techniques. In the majority of cases, electrospray mass spectrometry (ES-MS) has become the default ionisation technique. However, due to the absence of fragment ions in the resulting spectra, tandem mass spectrometry (MS/MS) is required to provide structural information for the identification of an unknown analyte. This work discusses the first steps of an investigation into the fragmentation pathways taking place in electrospray tandem mass spectrometry. The ultimate goal for this project is to set general fragmentation rules for non-peptidic, pharmaceutical, combinatorial compounds. As an aid, an artificial intelligence (AI) software package is used to facilitate interpretation of the spectra. This initial study has focused on determining the fragmentation rules for some classes of compound types that fit the remit as outlined above. Based on studies carried out on several combinatorial libraries of these compounds, it was established that different classes of drug molecules follow unique fragmentation pathways. In addition to these general observations, the specific ionisation processes and the fragmentation pathways involved in the electrospray mass spectra of these systems were explored. The ultimate goal will be to incorporate our findings into the computer program and allow identification of an unknown, non-peptidic compound following insertion of its ES-MS/MS spectrum into the AI package. The work herein demonstrates the potential benefit of such an approach in addressing the issue of high-throughput, automated MS/MS data interpretation. Copyright 2003 John Wiley & Sons, Ltd.

Isobar contributions to the imaginary part of the optical-model potential for finite nuclei

International Nuclear Information System (INIS)

Hjort-Jensen, M.; Borromeo, M.; Muether, H.; Polls, A.

1992-03-01

A recently developed non-relativistic method for calculating the nucleon optical-model potential has been employed to evaluate the contributions from isobaric degrees of freedom to the imaginary part of the nucleon optical-model potential. To evaluate the imaginary part of the optical-model potential, the authors include the contributions from terms to second order in the Brueckner G-matrix with and without the inclusion of isobars Δ. Results for 16 O are presented in this work. The contributions to the imaginary part are given by the two-particle-one-hole (2p1h) and three-particle-two-hole (3p2h) diagrams. The latter contributes at negative energies only and the contribution from isobar intermediate states is rather small. The 2p1h receives significant contributions from isobars at energies near the resonance and above the threshold for the excitation of ΔΔ states. In particular, the importance of ΔΔ configurations is rather sensitive to the treatment of short-range correlations. The parameterization of the self-energy in terms of local potentials is discussed. The depletion of the occupation of the single-particle orbits due to nucleon-nucleon correlations and Δ excitations is evaluated. 49 refs., 14 figs., 3 tabs

Role of rho exchange in isobar contributions to the NN interaction

International Nuclear Information System (INIS)

Bagnoud, X.; Holinde, K.; Machleidt, R.

1984-01-01

The fourth-order noniterative diagrams of πrho exchange involving nucleon-isobar intermediate states are evaluated in momentum space in the framework of noncovariant perturbation theory. It is shown that the sum of all time orderings (iterative plus noniterative) can be reasonably well approximated by twice the isoscalar piece of the iterative ones (which are much simpler to evaluate). The same approximation is used in order to describe the sum of all time orderings for the corresponding diagrams involving double-isobar intermediate states. The role of these contributions is studied in NN scattering. Especially, it is investigated whether such contributions can quantitatively replace part of the ω-exchange contribution used in one-boson-exchange models

MEASUREMENT OF PYRETHROID RESIDUES IN ENVIRONMENTAL AND FOOD SAMPLES BY ENHANCED SOLVENT EXTRACTION/SUPERCRITICAL FLUID EXTRACTION COUPLED WITH GAS CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

Science.gov (United States)

The abstract summarizes pyrethorid methods development research. It provides a summary of sample preparation and analytical techniques such as supercritical fluid extraction, enhance solvent extraction, gas chromatography and tandem mass spectrometry.

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

Directory of Open Access Journals (Sweden)

Santosh Ghatol

2013-04-01

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

Effect of particle fluctuation on isoscaling and isobaric yield ratio of nuclear multifragmentation

International Nuclear Information System (INIS)

Mallik, Swagata; Chaudhuri, Gargi

2013-01-01

Isoscaling and isobaric yield ratio parameters are compared from canonical and grand canonical ensembles when applied to multifragmentation of finite nuclei. Source dependence of isoscaling parameters and source and isospin dependence of isobaric yield ratio parameters are examined in the framework of the canonical and the grand canonical models. It is found that as the nucleus fragments more, results from both the ensembles converge and observables calculated from the canonical ensemble coincide more with those obtained from the formulae derived using the grand canonical ensemble

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

Directory of Open Access Journals (Sweden)

Ganesh S. Moorthy

2015-07-01

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

Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone

DEFF Research Database (Denmark)

Jensen, Marie Aarrebo; Hansen, Åse Marie; Abrahamsson, Peter

2011-01-01

saliva. We used liquid-liquid extraction (LLE) followed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS) recorded in positive ion mode. Saliva samples were collected by spitting directly into tubes and 250 µL were used for analysis. The limits of detection were 4...

Determination of nifedipine in dog plasma by high-performance liquid chromatography with tandem mass spectrometric detection.

Science.gov (United States)

Pan, Xigui; Zhou, Shunchang; Fu, Qinqin; Hu, Xianming; Wu, Jianhong

2014-07-01

Nifedipine is a dihydropyridine calcium channel blocker used widely in the management of hypertension and other cardiovascular disorders. In this work, a simple, rapid and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated to determine nifedipine in dog plasma using nimodipine as the internal standard. Chromatographic separation was carried out on a C₈ column. The mobile phase consisted of a mixture of acetonitrile, water and formic acid (60:40:0.2, v/v/v) at a flow rate of 0.5 mL/min. Detection was performed on a triple quadrupole tandem mass spectrometer in selected reaction monitoring mode via an atmospheric pressure chemical ionization source. The method has a lower limit of quantification of 0.20 ng/mL with consumption of plasma as low as 0.05 mL. The linear calibration curves were obtained in the concentration range of 0.20-50.0 ng/mL (r = 0.9948). The recoveries of the liquid extraction method were 74.5-84.1%. Intra-day and inter-day precisions were 4.1-8.8 and 6.7-7.4%, respectively. The quantification was not interfered with by other plasma components and the method was applied to determine nifedipine in plasma after a single oral administration of two controlled-release nifedipine tablets to beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.

Tandem mass spectrometry of human tryptic blood peptides calculated by a statistical algorithm and captured by a relational database with exploration by a general statistical analysis system.

Science.gov (United States)

Bowden, Peter; Beavis, Ron; Marshall, John

2009-11-02

A goodness of fit test may be used to assign tandem mass spectra of peptides to amino acid sequences and to directly calculate the expected probability of mis-identification. The product of the peptide expectation values directly yields the probability that the parent protein has been mis-identified. A relational database could capture the mass spectral data, the best fit results, and permit subsequent calculations by a general statistical analysis system. The many files of the Hupo blood protein data correlated by X!TANDEM against the proteins of ENSEMBL were collected into a relational database. A redundant set of 247,077 proteins and peptides were correlated by X!TANDEM, and that was collapsed to a set of 34,956 peptides from 13,379 distinct proteins. About 6875 distinct proteins were only represented by a single distinct peptide, 2866 proteins showed 2 distinct peptides, and 3454 proteins showed at least three distinct peptides by X!TANDEM. More than 99% of the peptides were associated with proteins that had cumulative expectation values, i.e. probability of false positive identification, of one in one hundred or less. The distribution of peptides per protein from X!TANDEM was significantly different than those expected from random assignment of peptides.

Study on inclusive production of Δ++ and Δ0 isobars in K-p interactions at 32 GeV/c

International Nuclear Information System (INIS)

Babintsev, V.V.; Bogolyubskij, M.Yu.; Bumazhnov, V.A.

1984-01-01

Properties of inclusive production of Δ ++ and Δ 0 isobars are studied using the total statistics (approximately 1.15x10 5 inelastic interactions) of the K - p experiment at 32 GeV/c. It is found that the Δ ++ and Δ 0 inclusive production cross sections are σ(Δ ++ )=1.71+-0.14 mb, σ(Δ 0 )=1.27+-0.25 mb. Some production differential cross sections for those isobars are reconstructed. Angular characteristics of Δ ++ decay are considered. It is shown that the principel part of the Δ ++ - and Δ 0 - isobars is produced peripherally (x ++ and Δ 0 distributions coincide in the main, which indicates that the same mechanism is controlling the isobar production

Simultaneous determination of three pesticides and their metabolites in unprocessed foods using ultraperformance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Rong, Lili; Wu, Xiaohu; Xu, Jun; Dong, Fengshou; Liu, Xingang; Pan, Xinglu; Du, Pengqiang; Wei, Dongmei; Zheng, Yongquan

2018-02-01

We have developed a rapid, multi-compound analytical method for measuring residues of the pesticides thiamethoxam and its metabolite, clothianidin; fipronil and its three metabolites, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl; and pyraclostrobin in unprocessed foods (rice, corn, cucumbers, tomatoes, apples, and bananas) by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Acetonitrile was used as the extraction solvent, and an octadecylsilane-dispersive SPE was used to clean up the analytes, which were then separated through a UPLC HSS T3 column connected to a tandem mass spectrometer via an electrospray ionisation source. The linearity of this method for the target analytes was excellent (R 2  ≥0.990) in the concentration range of 5-1000 μg kg -1 . The average recoveries of the seven compounds at concentrations of 10, 100, and 1000 μg kg -1 from six spiked matrix samples ranged from 73.6 to 110.6%, all with RSD values of ≤19.7%. The limit of quantification was 10 μg kg -1 . The method validated the effectiveness of the method for routine monitoring the residue of these pesticides and their metabolites in foods.

High-performance liquid chromatography coupled with tandem mass spectrometry technology in the analysis of Chinese Medicine Formulas: A bibliometric analysis (1997-2015).

Science.gov (United States)

He, Xi-Ran; Li, Chun-Guang; Zhu, Xiao-Shu; Li, Yuan-Qing; Jarouche, Mariam; Bensoussan, Alan; Li, Ping-Ping

2017-01-01

There is a recognized challenge in analyzing traditional Chinese medicine formulas because of their complex chemical compositions. The application of modern analytical techniques such as high-performance liquid chromatography coupled with a tandem mass spectrometry has improved the characterization of various compounds from traditional Chinese medicine formulas significantly. This study aims to conduct a bibliometric analysis to recognize the overall trend of high-performance liquid chromatography coupled with tandem mass spectrometry approaches in the analysis of traditional Chinese medicine formulas, its significance and possible underlying interactions between individual herbs in these formulas. Electronic databases were searched systematically, and the identified studies were collected and analyzed using Microsoft Access 2010, Graph Pad 5.0 software and Ucinet software package. 338 publications between 1997 and 2015 were identified, and analyzed in terms of annual growth and accumulated publications, top journals, forms of traditional Chinese medicine preparations and highly studied formulas and single herbs, as well as social network analysis of single herbs. There is a significant increase trend in using high-performance liquid chromatography coupled with tandem mass spectrometry related techniques in analysis of commonly used forms of traditional Chinese medicine formulas in the last 3 years. Stringent quality control is of great significance for the modernization and globalization of traditional Chinese medicine, and this bibliometric analysis provided the first and comprehensive summary within this field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proton nucleus elastic scattering at 800 MeV: the role of intermediate isobars

International Nuclear Information System (INIS)

Auger, J.P.; Maillet, J.P.; Lazard, C.; Lombard, R.J.

1984-10-01

Proton nucleus elastic scattering at 800 MeV has been calculated in the Glauber model for 16 O, 40 Ca, 48 Ca and 208 Pb. Nuclear densities are taken from Hartree-Fock-BCS calculations. For the nucleon-nucleon amplitudes, use is made of two recent phase shift analysis. The effects of intermediate isobars are included by means of a simple model. The results show that the experimental data are qualitatively understood. The polarization turns out to be quite sensitive to the intermediate isobar effects, which consequently need to be calculated more carefully

Determination of albendazole sulfoxide in human plasma by using liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Saraner, Nihal; Özkan, Güler Yağmur; Güney, Berrak; Alkan, Erkin; Burul-Bozkurt, Nihan; Sağlam, Onursal; Fikirdeşici, Ezgi; Yıldırım, Mevlüt

2016-06-01

A rapid, simple and sensitive method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination of albendazole sulfoxide (ABZOX) in human plasma. The plasma samples were extracted by protein precipitation using albendazole sulfoxide-d3 as internal standard (IS). The chromatographic separation was performed on Waters Xbridge C18Column (100×4.6mm, 3.5μm) with a mobile phase consisting of ammonia solution, water and methanol at a flow rate of 0.70mL/min. ABZOX was detected and identified by mass spectrometry with electrospray ionization (ESI) in positive ion and multiple-reaction monitoring (MRM) mode. The method was linear in the range of 3-1500ng/mL for ABZOX. This method was successfully applied to the bioequivalence study in human plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of thromboxanes, leukotrienes and lipoxins using high-temperature capillary liquid chromatography-tandem mass spectrometry and on-line sample preparation

DEFF Research Database (Denmark)

Dahl, Sandra Rinne; Kleiveland, Charlotte Ramstad; Kassem, Moustapha

2009-01-01

An on-line strong cation-exchange (SCX)-reversed-phase (RP) capillary liquid chromatographic (cLC) method with ion-trap tandem mass spectrometric (IT-MS/MS) detection for the simultaneous determination of thromboxane (TX) B(2), TXB(3), leukotriene (LT) B(4), LTD(4) and lipoxin (LX) A(4) in cell...

Simultaneous determination of tyrosine, phenylalanine and deoxyguanosine oxidation products by liquid chromatography-tandem mass spectrometry as non-invasive biomarkers for oxidative damage

NARCIS (Netherlands)

Orhan, Hilmi; Vermeulen, Nico P E; Tump, Cornelis; Zappey, Herman; Meerman, John H N

2004-01-01

We developed an isotope dilution HPLC-atmospheric pressure chemical ionization-tandem mass spectrometry (HPLC-APCI-MS/MS) method for the simultaneous determination of p-tyrosine, phenylalanine, o,o'-dityrosine, m-tyrosine, o-tyrosine, 3-chlorotyrosine and 3-nitrotyrosine and

Data in support for the measurement of serum 25-hydroxyvitamin D (25OHD by tandem mass spectrometry

Directory of Open Access Journals (Sweden)

M.E. Jensen

2016-09-01

Full Text Available This article provides data and a method related to a research paper entitled “Assessing vitamin D nutritional status: is capillary blood adequate?” (Jensen et al., 2016 [1]. Circulating 25OHD, the accepted biomarker of the vitamin D nutritional status, is routinely measured by automated immunoassays, that although may be performed in hospital central laboratories, often suffer from a lack of specificity with regards to the different vitamin D metabolites, “Measurement of circulating 25-hydroxyvitamin D: a historical review” (Le Goff et al., 2015 [2]. Mass spectrometry offers this specificity. This article describes the performance of an in-house tandem mass spectrometry method for the individual measurement of 25OHD3, 25OHD2 and 3-épi-25OHD3. Keywords: Vitamin D, 25-hydroxyvitamin D, Mass spectrometry

Isobars of an ideal Bose gas within the grand canonical ensemble

International Nuclear Information System (INIS)

Jeon, Imtak; Park, Jeong-Hyuck; Kim, Sang-Woo

2011-01-01

We investigate the isobar of an ideal Bose gas confined in a cubic box within the grand canonical ensemble for a large yet finite number of particles, N. After solving the equation of the spinodal curve, we derive precise formulas for the supercooling and the superheating temperatures that reveal an N -1/3 or N -1/4 power correction to the known Bose-Einstein condensation temperature in the thermodynamic limit. Numerical computations confirm the accuracy of our analytical approximation, and further show that the isobar zigzags on the temperature-volume plane if N≥14 393. In particular, for the Avogadro's number of particles, the volume expands discretely about 10 5 times. Our results quantitatively agree with a previous study on the canonical ensemble within 0.1% error.

Sensitive, automatic method for the determination of diazepam and its five metabolites in human oral fluid by online solid-phase extraction and liquid chromatography with tandem mass spectrometry

DEFF Research Database (Denmark)

Jiang, Fengli; Rao, Yulan; Wang, Rong

2016-01-01

A novel and simple online solid-phase extraction liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of diazepam and its five metabolites including nordazepam, oxazepam, temazepam, oxazepam glucuronide, and temazepam glucuronide...... in human oral fluid. Human oral fluid was obtained using the Salivette(®) collection device, and 100 μL of oral fluid samples were loaded onto HySphere Resin GP cartridge for extraction. Analytes were separated on a Waters Xterra C18 column and quantified by liquid chromatography with tandem mass...

Quantification of rifampicin in human plasma and cerebrospinal fluid by a highly sensitive and rapid liquid chromatographic–tandem mass spectrometric method

OpenAIRE

Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A.

2012-01-01

A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC–MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monit...

Residue analysis of sixty pesticides in red swamp crayfish using QuEChERS with high-performance liquid chromatography-tandem mass spectrometry

Science.gov (United States)

In this study, a multi-residue analytical method using QuEChERS extraction and dispersive solid-phase extraction (d-SPE) cleanup followed by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) was developed for rapid determination of 60 pesticide residues in whole crayfish a...

[Rapid screening the alkaloids of poppy shell in hot pot condiment, beef noodle soup and seasoning by direct analysis in real time-tandem mass spectrometry].

Science.gov (United States)

Zhang, Baile; Gao, Lihong; Xie, Yingshuang; Zhou, Wei; Chen, Xiaofeng; Lei, Chunni; Zhang, Huan

2017-07-08

A direct analysis in real time tandem mass spectrometry (DART-MS/MS) method was established for quickly screening five illegally added alkaloids of poppy shell from the hot pot condiment, beef noodle soup and seasoning. The samples were extracted and purified by acetonitrile, and then injected under the conditions of ionization temperature of 300℃, grid electrode voltage of 150 V and sampling rate of 0.8 mm/s using DART in the positive ion mode. The determination was conducted by tandem mass spectrometry in positive ESI mode under multiple reaction monitoring (MRM) mode. The method is simple and rapid, and can meet the requirement of rapid screening and analysis of large quantities of samples.

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

OpenAIRE

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

2015-01-01

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

[Qualitative and quantitative analysis of amygdalin and its metabolite prunasin in plasma by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

Science.gov (United States)

Gao, Meng; Wang, Yuesheng; Wei, Huizhen; Ouyang, Hui; He, Mingzhen; Zeng, Lianqing; Shen, Fengyun; Guo, Qiang; Rao, Yi

2014-06-01

A method was developed for the determination of amygdalin and its metabolite prunasin in rat plasma after intragastric administration of Maxing shigan decoction. The analytes were identified by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the qualitative analysis of amygdalin and prunasin in the plasma sample was performed on a Shim-pack XR-ODS III HPLC column (75 mm x 2.0 mm, 1.6 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on a Triple TOF 5600 quadrupole time of flight mass spectrometer. The quantitative analysis of amygdalin and prunasin in the plasma sample was performed by separation on an Agilent C18 HPLC column (50 mm x 2.1 mm, 1.7 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on an AB Q-TRAP 4500 triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The qualitative analysis results showed that amygdalin and its metabolite prunasin were detected in the plasma sample. The quantitative analysis results showed that the linear range of amygdalin was 1.05-4 200 ng/mL with the correlation coefficient of 0.999 0 and the linear range of prunasin was 1.25-2 490 ng/mL with the correlation coefficient of 0.997 0. The method had a good precision with the relative standard deviations (RSDs) lower than 9.20% and the overall recoveries varied from 82.33% to 95.25%. The limits of detection (LODs) of amygdalin and prunasin were 0.50 ng/mL. With good reproducibility, the method is simple, fast and effective for the qualitative and quantitative analysis of the amygdalin and prunasin in plasma sample of rats which were administered by Maxing shigan decoction.

Quantitative analysis of a novel antimicrobial peptide in rat plasma by ultra performance liquid chromatography–tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Ruo-Wen Zhang

2011-08-01

Full Text Available We described the first results of a quantitative ultra performance liquid chromatography–tandem mass spectrometry method for a novel antimicrobial peptide (phylloseptin, PSN-1. Chromatographic separation was accomplished on a Waters bridged ethyl hybrid (BEH C18 (50 mm×2.1 mm, 1.7 μm column with acetonitrile–water (25:75, v/v as isocratic mobile phase. Mass spectrometry detection was performed in the positive electrospray ionization mode and by monitoring of the transitions at m/z 679.6/120, 509.6/120 (PSN-1 and m/z 340.7/165 (Thymopentin, IS. Protein precipitation was investigated and the recovery was satisfactory (above 82%. The method was shown to be reproducible and reliable with intra-day precision below 5.3%, inter-day precision below 14.2%, and linear range from 0.02 to 2 μg/mL with r>0.994. The method was successfully applied to a pharmacokinetic study of PSN-1 in rats after intravenous administration. Keywords: Antimicrobial peptide, Phylloseptin, Ultra performance liquid chromatography–tandem mass spectrometry, Pharmacokinetic

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....

21 CFR 862.1055 - Newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

Science.gov (United States)

2010-04-01

..., free carnitine, and acylcarnitines using tandem mass spectrometry. 862.1055 Section 862.1055 Food and... screening test system for amino acids, free carnitine, and acylcarnitines using tandem mass spectrometry. (a) Identification. A newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

Determination of long-lived radionuclide (10Be, 41Ca, 129I) concentrations in nuclear waste by accelerator mass spectrometry

International Nuclear Information System (INIS)

Nottoli, Emmanuelle; Bienvenu, Philippe; Labet, Alexandre; Bertaux, Maite; Bourles, Didier; Arnold, Maurice

2013-01-01

Radiological characterization of nuclear waste is essential for storage sites management. However, most of Long-Lived Radionuclides (LLRN), important for long-term management, are difficult to measure since concentration levels are very low and waste matrices generally complex. In an industrial approach, LLRN concentrations are not directly measured in waste samples but assessed from scaling factors with respect to easily measured gamma emitters. Ideally, the key nuclide chosen ( 60 Co, 137 Cs) should be produced by a similar mechanism (fission or activation) as the LLRN of interest and should have similar physicochemical properties. However, the uncertainty on the scaling factors, determined from experimental and/or calculation data, can be quite important. Consequently, studies are performed to develop analytical procedures which would lead to determine precisely the concentration of LLRN in nuclear waste. In this context, the aim of this study was to determine the concentrations of three LLRN: 129 I (T 1/2 = 15.7*10 6 a), 41 Ca (T 1/2 = 9.94*10 4 a) and 10 Be (T 1/2 = 1.387*10 6 a) in spent resins used for primary fluid purification in Pressurized Water Reactors using Accelerator Mass Spectrometry (AMS) for measurement. The AMS technique combined mass spectrometry and nuclear physics to achieve highly efficient molecular and elemental isobars separation. Energies of several Million Electron-Volt transferred to the ions in the first accelerating part of specifically developed tandem accelerators lead to molecular isobars destruction through interaction with the argon gas used to strip the injected negative ions to positive ones. At the exit of the tandem accelerator, the energy acquired in both accelerating parts allows an elemental isobars separation based on their significantly different energy loss (dE) while passing through a thickness of matter dx that is proportional to their atomic number (Z) and inversely proportional to ions velocity (v) according to the

Ultra-high-performance liquid chromatography-tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp

NARCIS (Netherlands)

Chen, G.; Hoptroff, M.; Fei, X.; Su, Y.; Janssen, H.-G.

2013-01-01

A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal

Simultaneous identification of multiple β-lactamases in Acinetobacter baumannii in relation to carbapenem and ceftazidime resistance, using liquid chromatography-tandem mass spectrometry

NARCIS (Netherlands)

Trip, H.; Mende, K.; Majchrzykiewicz-Koehorst, J.A.; Sedee, N.J.A.; Hulst, A.G.; Jansen, H.J.; Murray, C.K.; Paauw, A.

2015-01-01

Shotgun proteomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to detect β-lactamases in clinical Acinetobacter baumannii isolates. The correlation of the detection of β-lactamase proteins (rather than PCR detection of the corresponding genes) with the resistance

Tandem mass spectrometry characteristics of polyester anions and cations formed by electrospray ionization.

Science.gov (United States)

Arnould, Mark A; Buehner, Rita W; Wesdemiotis, Chrys; Vargas, Rafael

2005-01-01

Electrospray ionization of polyesters composed of isophthalic acid and neopentyl glycol produces carboxylate anions in negative mode and mainly sodium ion adducts in positive mode. A tandem mass spectrometry (MS/MS) study of these ions in a quadrupole ion trap shows that the collisionally activated dissociation pathways of the anions are simpler than those of the corresponding cations. Charge-remote fragmentations predominate in both cases, but the spectra obtained in negative mode are devoid of the complicating cation exchange observed in positive mode. MS/MS of the Na(+) adducts gives rise to a greater number of fragments but not necessarily more structural information. In either positive or negative mode, polyester oligomers with different end groups fragment by similar mechanisms. The observed fragments are consistent with rearrangements initiated by the end groups. Single-stage ESI mass spectra also are more complex in positive mode because of extensive H/Na substitutions; this is also true for matrix-assisted laser desorption ionization (MALDI) mass spectra. Hence, formation and analysis of anions might be the method of choice for determining block length, end group structure and copolymer sequence, provided the polyester contains at least one carboxylic acid end group that is ionizable to anions.

Inductively coupled plasma – Tandem mass spectrometry (ICP-MS/MS): A powerful and universal tool for the interference-free determination of (ultra)trace elements – A tutorial review

Energy Technology Data Exchange (ETDEWEB)

Balcaen, Lieve; Bolea-Fernandez, Eduardo [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium); Resano, Martín [University of Zaragoza, Department of Analytical Chemistry, Pedro Cerbuna 12, E-50009 Zaragoza (Spain); Vanhaecke, Frank, E-mail: Frank.Vanhaecke@UGent.be [Ghent University, Department of Analytical Chemistry, Krijgslaan 281-S12, B-9000 Ghent (Belgium)

2015-09-24

This paper is intended as a tutorial review on the use of inductively coupled plasma – tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H{sub 2}, O{sub 2} and NH{sub 3}, also the use of promising alternative gases, such as CH{sub 3}F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis. - Highlights: • First review on tandem ICP-mass spectrometry (ICP-MS/MS). • Clear description of operating principles of ICP-MS/MS. • Description on how to make use of product ion scans, precursor ion scans and neutral gain scans in method development. • Overview of applications published so far.

Inductively coupled plasma – Tandem mass spectrometry (ICP-MS/MS): A powerful and universal tool for the interference-free determination of (ultra)trace elements – A tutorial review

International Nuclear Information System (INIS)

Balcaen, Lieve; Bolea-Fernandez, Eduardo; Resano, Martín; Vanhaecke, Frank

2015-01-01

This paper is intended as a tutorial review on the use of inductively coupled plasma – tandem mass spectrometry (ICP-MS/MS) for the interference-free quantitative determination and isotope ratio analysis of metals and metalloids in different sample types. Attention is devoted both to the instrumentation and to some specific tools and procedures available for advanced method development. Next to the more typical reaction gases, e.g., H_2, O_2 and NH_3, also the use of promising alternative gases, such as CH_3F, is covered, and the possible reaction pathways with those reactive gases are discussed. A variety of published applications relying on the use of ICP-MS/MS are described, to illustrate the added value of tandem mass spectrometry in (ultra)trace analysis. - Highlights: • First review on tandem ICP-mass spectrometry (ICP-MS/MS). • Clear description of operating principles of ICP-MS/MS. • Description on how to make use of product ion scans, precursor ion scans and neutral gain scans in method development. • Overview of applications published so far.

Isobaric thermal expansivity behaviour against temperature and pressure of associating fluids

Energy Technology Data Exchange (ETDEWEB)

Navia, Paloma; Troncoso, Jacobo [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis, E-mail: romani@uvigo.e [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain)

2010-01-15

In order to study the influence of association on the isobaric thermal expansivity, this magnitude has been experimentally determined for a set of associating fluids within the temperature and pressure intervals (278.15 to 348.15) K and (5 to 55) MPa by means of calorimetric measurements. The 1-alcohol series, from methanol to 1-decanol, 2-pentanol, 3-pentanol, and 1-pentylamine were selected. With a view on checking the quality of the experimental data, they are compared with available literature values; good coherence was obtained for most of the studied liquids. The analysis of the experimental results reveals that the association capability presents a strong influence not only on the value of the isobaric thermal expansivity itself, but also on its behaviour against temperature and pressure.

Isobaric thermal expansivity behaviour against temperature and pressure of associating fluids

International Nuclear Information System (INIS)

Navia, Paloma; Troncoso, Jacobo; Romani, Luis

2010-01-01

In order to study the influence of association on the isobaric thermal expansivity, this magnitude has been experimentally determined for a set of associating fluids within the temperature and pressure intervals (278.15 to 348.15) K and (5 to 55) MPa by means of calorimetric measurements. The 1-alcohol series, from methanol to 1-decanol, 2-pentanol, 3-pentanol, and 1-pentylamine were selected. With a view on checking the quality of the experimental data, they are compared with available literature values; good coherence was obtained for most of the studied liquids. The analysis of the experimental results reveals that the association capability presents a strong influence not only on the value of the isobaric thermal expansivity itself, but also on its behaviour against temperature and pressure.

ΛN-ΣN interaction with isobar coupling and six-quark resonances

International Nuclear Information System (INIS)

Greenberg, W.R.; Lomon, E.L.

1993-01-01

The long-range ΛN-ΣN interaction is modeled by a configuration-space meson-exchange potential matrix coupling to channels with Δ and Σ(1385) isobars. An inner boundary condition, based on R-matrix theory, replaces form factors for short-range effects and includes the effects of free quark configurations. An excellent fit is obtained to the available data, with only the energy-independent boundary conditions as free parameters. The effect of isobar thresholds is shown to be substantial in several partial waves and is crucial to the understanding of the higher-energy ΛN elastic scattering data. The positions and widths of [q(1s 1/2 )] 5 s(1s 1/2 ) quark exotics are predicted

Dependence of isobar-analog state properties on variable part of Coulomb potential

International Nuclear Information System (INIS)

Dzhafarov, I.G.; Kuliev, A.A.; Salamov, D.I.

1986-01-01

Within the framework of the self-consistent approach and with the method of strength functions the fragmentation of isobar-analog state (IAS) properties for all isobarie 0 + -states is investigated. Microscopic values of IAS energy, matrix elements of allowed and forbidden Fermi transitions as well as isospin impurity values in ground states of parent nuclei are obtained. Numerical calculations carried out for 42 Ca 42 Sc, 48 Ca 48 Sc, 64 Zn 64 Ga, 66 Zn 66 Ga, 90 Zr 90 Nb, 208 Pb 208 Bi isobaric nuclei with Woods-Saxon potential, are compared with predictions of different approches and experiment. The developed model by the authors permits to describe sufficiently well the experimental data

Evaluation of the decay characteristics of isobars with A=95

International Nuclear Information System (INIS)

Grigor'yan, Yu.I.; Sokolovskij, L.L.; Chukreev, F.E.; Shurshikov, E.N.

1978-06-01

Energies and intensities of the beta transitions, gamma photons and conversion electrons accompanying beta decay and electron capture, internal conversion coefficients, energy levels and lifetimes of the ground and excited states of isobars with A=95 are evaluated and presented in tables and diagrams

Application of Tandem Two-Dimensional Mass Spectrometry for Top-Down Deep Sequencing of Calmodulin.

Science.gov (United States)

Floris, Federico; Chiron, Lionel; Lynch, Alice M; Barrow, Mark P; Delsuc, Marc-André; O'Connor, Peter B

2018-06-04

Two-dimensional mass spectrometry (2DMS) involves simultaneous acquisition of the fragmentation patterns of all the analytes in a mixture by correlating their precursor and fragment ions by modulating precursor ions systematically through a fragmentation zone. Tandem two-dimensional mass spectrometry (MS/2DMS) unites the ultra-high accuracy of Fourier transform ion cyclotron resonance (FT-ICR) MS/MS and the simultaneous data-independent fragmentation of 2DMS to achieve extensive inter-residue fragmentation of entire proteins. 2DMS was recently developed for top-down proteomics (TDP), and applied to the analysis of calmodulin (CaM), reporting a cleavage coverage of about ~23% using infrared multiphoton dissociation (IRMPD) as fragmentation technique. The goal of this work is to expand the utility of top-down protein analysis using MS/2DMS in order to extend the cleavage coverage in top-down proteomics further into the interior regions of the protein. In this case, using MS/2DMS, the cleavage coverage of CaM increased from ~23% to ~42%. Graphical Abstract Two-dimensional mass spectrometry, when applied to primary fragment ions from the source, allows deep-sequencing of the protein calmodulin.

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

NARCIS (Netherlands)

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

2006-01-01

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

Dispersive solid phase extraction combined with ion-pair ultra high-performance liquid chromatography tandem mass spectrometry for quantification of nucleotides in Lactococcus lactis

DEFF Research Database (Denmark)

Magdenoska, Olivera; Martinussen, Jan; Thykær, Jette

2013-01-01

solid phase extraction with charcoal and subsequent analysis with ion-pair liquid chromatography coupled with electrospray ionization tandem mass spectrometry was established for quantification of intracellular pools of the 28 most important nucleotides. The method can handle extracts where cells leak...

Optimization of a ΔE - E detector for 41Ca AMS

Science.gov (United States)

Hosoya, Seiji; Sasa, Kimikazu; Matsunaka, Tetsuya; Takahashi, Tsutomu; Matsumura, Masumi; Matsumura, Hiroshi; Sundquist, Mark; Stodola, Mark; Sueki, Keisuke

2017-09-01

A series of nuclides (14C, 26Al, and 36Cl) was measured using the 12UD Pelletron tandem accelerator before replacement by the horizontal 6 MV tandem accelerator at the University of Tsukuba Tandem Accelerator Complex (UTTAC). This paper considers the modification of the accelerator mass spectrometry (AMS) measurement parameters to suit the current 6 MV tandem accelerator setup (e.g., terminal voltage, detected ion charge state, gas pressure, and entrance window material in detector). The Particle and Heavy Ion Transport code System (PHITS) was also used to simulate AMS measurement to determine the best conditions to suppress isobaric interference. The spectra of 41Ca and 41K were then successfully separated and their nuclear spectra were identified; the system achieved a background level of 41Ca/40Ca ∼ 6 ×10-14 .

Characterization of bisphenol A metabolites produced by Portulaca oleracea cv. by liquid chromatography coupled with tandem mass spectrometry.

Science.gov (United States)

Watanabe, Ippei; Harada, Kazuo; Matsui, Takeshi; Miyasaka, Hitoshi; Okuhata, Hiroshi; Tanaka, Satoshi; Nakayama, Hideki; Kato, Ko; Bamba, Takeshi; Hirata, Kazumasa

2012-01-01

The garden plant portulaca (Portulaca oleracea cv.) efficiently removes bisphenol A (BPA), an endocrine-disrupting chemical, from a hydroponic solution, but the molecular mechanisms underlying BPA metabolism by portulaca remain unclear. In this study, BPA metabolites converted by portulaca were analyzed by liquid chromatography coupled with tandem mass spectrometry. We observed the hydroxylation of BPA and the oxidization of it to quinone. Polyphenol oxidases are likely to contribute to BPA degradation by portulaca.

Tandem Mass Spectrometry of Modified and Platinated Oligoribonucleotides

Science.gov (United States)

Nyakas, Adrien; Stucki, Silvan R.; Schürch, Stefan

2011-05-01

Therapeutic approaches for treatment of various diseases aim at the interruption of transcription or translation. Modified oligonucleotides, such as 2'- O-methyl- and methylphosphonate-derivatives, exhibit high resistance against cellular nucleases, thus rendering application for, e.g., antigene or antisense purposes possible. Other approaches are based on administration of cross-linking agents, such as cis-diamminedichloroplatinum(II) (cisplatin, DDP), which is still the most widely used anticancer drug worldwide. Due to the formation of 1,2-intrastrand cross links at adjacent guanines, replication of the double-strand is disturbed, thus resulting in significant cytotoxicity. Evidence for the gas-phase dissociation mechanism of platinated RNA is given, based on nano-electrospray ionization high-resolution multistage tandem mass spectrometry (MS n ). Confirmation was found by investigating the fragmentation pattern of platinated and unplatinated 2'-methoxy oligoribonucleotide hexamers and their corresponding methylphosphonate derivatives. Platinated 2'-methoxy oligoribonucleotides exhibit a similar gas-phase dissociation behavior as the corresponding DNA and RNA sequences, with the 3'-C-O bond adjacent to the vicinal guanines being cleaved preferentially, leading to wx-ion formation. By examination of the corresponding platinated methylphosphonate derivatives of the 2'-methoxy oligoribonucleotides, the key role of the negatively charged phosphate oxygen atoms in direct proximity to the guanines was proven. The significant alteration of fragmentation due to platination is demonstrated by comparison of the fragment ion patterns of unplatinated and platinated 2'- O-methyl- and 2'- O-methyl methylphosphonate oligoribonucleotides, and the results obtained by H/D exchange experiments.

Monitoring salivary melatonin concentrations in children with sleep disorders using liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Khan, Sohil A; George, Rani; Charles, Bruce G; Taylor, Paul J; Heussler, Helen S; Cooper, David M; McGuire, Treasure M; Pache, David; Norris, Ross L G

2013-06-01

Melatonin is synthesized in the pineal gland and is an important circadian phase marker, especially in the determination of sleep patterns. Both temporary and permanent abnormal sleep patterns occur in children; therefore, it is desirable to have methods for monitoring melatonin in biological fluids in the diagnosis and treatment of such disorders. The objective of the study is to develop a liquid chromatography-tandem mass spectrometry method for the determination of melatonin in saliva and to apply it to monitoring salivary concentrations in children with sleep disorders. A deuterated internal standard (d7-melatonin) was added to a diluted saliva sample (20 µL) in an autosampler vial insert, and 50 µL were injected. Plasticware was strictly avoided, and all glassware was scrupulously cleaned and then baked at 120°C for at least 48 hours to obtain satisfactory performance. Reverse-phase chromatography was performed on a C8 column using a linear gradient elution profile comprising mobile phases A (0.1% aqueous formic acid) and B (15% methanol in acetonitrile containing 0.1% formic acid), pumped at a total flow rate of 0.8 mL/min. The run time was 8 minutes. After atmospheric pressure chemical ionization, mass spectrometric detection was in positive ion mode. Mass detection was by selected reaction monitoring mode with the following mass transitions used for quantification: melatonin, m/z 233.0 → 173.8 and d7-melatonin, m/z 240.0 → 178.3. Linearity (r > 0.999) was established from 3.9 to 1000 pg/mL. Imprecision (coefficient of variation percent) was less than 11%, and accuracy was 100-105% (7.0-900 pg/mL). The method was selective, and the mean (range) ratio of the slopes of calibrations in water to those in daytime saliva samples collected from 10 healthy adult subjects was 0.989 (0.982-0.997), indicating negligible matrix effects. The application of the assay was demonstrated in healthy adults and in children being clinically investigated for sleep

Measurement of tamsulosin in human serum by liquid chromatography–tandem mass spectrometry☆

Science.gov (United States)

Upreti, Rita; Homer, Natalie Z.M.; Naredo, Gregorio; Cobice, Diego F.; Hughes, Katherine A.; Stewart, Laurence H.; Walker, Brian R.; Andrew, Ruth

2013-01-01

A simple, sensitive and robust method to extract tamsulosin from human serum, and quantify by liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed and validated and is applicable as a measure of compliance in clinical research. Tamsulosin was extracted from human serum (100 μL) via liquid–liquid extraction with methyl tert-butyl ether (2 mL) following dilution with 0.1 M ammonium hydroxide (100 μL), achieving 99.9% analyte recovery. Internal standard, d9-finasteride, was synthesised in-house. Analyte and internal standard were separated on an Ascentis® Express C18 (100 mm × 3 mm, 2.7 μm) column using a gradient elution with mobile phases methanol and 2 mM aqueous ammonium acetate (5:95, v/v). Total run-time was 6 min. Tamsulosin was quantified using a triple quadrupole mass spectrometer operated in multi-reaction-monitoring (MRM) mode using positive electrospray ionisation. Mass transitions monitored for quantitation were: tamsulosin m/z 409 → 228 and d9-finasteride m/z 382 → 318, with the structural formulae of ions confirmed by Fourier transform ion cyclotron resonance mass spectrometry (within 10 ppm). The limit of quantitation was 0.2 ng/mL, and the method was validated in the linear range 0.2–50 ng/mL with acceptable inter- and intra-assay precision and accuracy and stability suitable for routine laboratory practice. The method was successfully applied to samples taken from research volunteers in a clinical study of benign prostatic hyperplasia. PMID:23743242

Liquid chromatography with tandem mass spectrometry quantification of urinary proanthocyanin A2 dimer and its potential use as a biomarker of cranberry intake

Science.gov (United States)

The lack of a biomarker for the consumption of cranberries has confounded the interpretation of several studies investigating the effect of cranberry products, especially juices, on health outcomes. The objectives of this pilot study were to develop a liquid chromatography tandem mass spectrometric ...

Hyphenation of supercritical fluid chromatography with tandem mass spectrometry for fast determination of four aflatoxins in edible oil.

Science.gov (United States)

Lei, Fang; Li, Chenglong; Zhou, Shuang; Wang, Dan; Zhao, Yunfeng; Wu, Yongning

2016-08-01

Aflatoxins (AFTs) are of great concern all over the world. Supercritical fluid chromatography (SFC) has the advantage of fast, high resolution and excellent compatibility with a broad range of organic solvents and samples, thus hyphenating SFC with tandem mass spectrometry (MS/MS) can be used for the easy and fast determination of AFTs in edible oils. Edible oil was spiked with isotope-labeled aflatoxin standards, diluted with hexane and extracted with acetonitrile. The extraction was directly loaded to an SFC apparatus and separated on a UPC(2) 2-EP column with CO2 -methanol gradient elution. A post-column make-up flow was introduced to facilitate mass spectrometry performance, and the mixture was analyzed by MS/MS with an electrospray ionization (ESI) source. The SFC conditions including separation column, modifier and sample solvent were optimized, and the four target aflatoxins were baseline separated. The ESI interface parameters were also investigated, implicating the make-up flow as a critical factor for sensitive determination by SFC-MS/MS. The LOQs for the AFTs were 0.05-0.12 μg L(-1) , while the RSDs were lower than 8.5%. Supercritical fluid chromatography was successfully coupled to tandem mass spectrometry to establish a simple, fast and sensitive method for the analysis of four aflatoxins in edible oil. This shows the combination of SFC-MS/MS has great potential in determination of trace contaminants in food. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Fluoride sample matrices and reaction cells — new capabilities for isotope measurements in accelerator mass spectrometry

Directory of Open Access Journals (Sweden)

Eliades J.

2012-04-01

Full Text Available Two new techniques, which extend the range of elements that can be analyzed by Accelerator Mass Spectrometry (AMS, and which increase its isobar selection capabilities, have been recently introduced. The first consists of embedding the sample material in a fluoride matrix (e.g. PbF2, which facilitates the production, in the ion source, of fluoride molecular anions that include the isotope of interest. In addition to forming anions with large electron binding energies and thereby increasing the range of analysable elements, in many cases by selection of a molecular form with a particular number of fluorine atoms, some isobar discrimination can be obtained. The second technique, for the significant reduction of atomic isobar interferences, is used following mass selection of the rare isotope. It consists of the deceleration, cooling and reaction of the rare mass beam with a gas, selected so that unwanted isobars are greatly attenuated in comparison with the isotope of interest. Proof of principle measurements for the analysis of 36C1 and 41Ca have provided encouraging results and work is proceeding on the integration of these techniques in a new AMS system planned for installation in late 2012 at the University of Ottawa.

Elemental analysis of coal by tandem laser induced breakdown spectroscopy and laser ablation inductively coupled plasma time of flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Dong, Meirong [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Oropeza, Dayana [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Chirinos, José [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Escuela de Química, Facultad de Ciencias, Universidad Central de Venezuela, Caracas 1041a (Venezuela, Bolivarian Republic of); González, Jhanis J. [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Lu, Jidong [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Mao, Xianglei [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Russo, Richard E., E-mail: RERusso@lbl.gov [Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States)

2015-07-01

The capabilities and analytical benefits of combined LIBS and LA-ICP-MS were evaluated for the analysis of coal samples. The ablation system consisted of a Nd:YAG laser operated 213 nm. A Czerny-turner spectrograph with ICCD detector and time-of-flight based mass spectrometer were utilized for LIBS and ICP-MS detection, respectively. This tandem approach allows simultaneous determination of major and minor elements (C, Si, Ca, Al, Mg), and trace elements (V, Ba, Pb, U, etc.) in the coal samples. The research focused on calibration strategies, specifically the use of univariate and multivariate data analysis on analytical performance. Partial least square regression (PLSR) was shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The correlation between measurements from these two techniques demonstrated that mass spectral data combined with LIBS emission measurements by PLSR improved the accuracy and precision for quantitative analysis of trace elements in coal. - Highlights: • Tandem LIBS LA-ICP-MS • Simultaneous determination of major and minor elements and trace elements in the coal samples. • Extended Dynamic Range • Correlation between LIBS with LA-ICP-MS demonstrated improved the accuracy and precision for quantitative analysis of coal.

Elemental analysis of coal by tandem laser induced breakdown spectroscopy and laser ablation inductively coupled plasma time of flight mass spectrometry

International Nuclear Information System (INIS)

Dong, Meirong; Oropeza, Dayana; Chirinos, José; González, Jhanis J.; Lu, Jidong; Mao, Xianglei; Russo, Richard E.

2015-01-01

The capabilities and analytical benefits of combined LIBS and LA-ICP-MS were evaluated for the analysis of coal samples. The ablation system consisted of a Nd:YAG laser operated 213 nm. A Czerny-turner spectrograph with ICCD detector and time-of-flight based mass spectrometer were utilized for LIBS and ICP-MS detection, respectively. This tandem approach allows simultaneous determination of major and minor elements (C, Si, Ca, Al, Mg), and trace elements (V, Ba, Pb, U, etc.) in the coal samples. The research focused on calibration strategies, specifically the use of univariate and multivariate data analysis on analytical performance. Partial least square regression (PLSR) was shown to minimize and compensate for matrix effects in the emission and mass spectra improving quantitative analysis by LIBS and LA-ICP-MS, respectively. The correlation between measurements from these two techniques demonstrated that mass spectral data combined with LIBS emission measurements by PLSR improved the accuracy and precision for quantitative analysis of trace elements in coal. - Highlights: • Tandem LIBS LA-ICP-MS • Simultaneous determination of major and minor elements and trace elements in the coal samples. • Extended Dynamic Range • Correlation between LIBS with LA-ICP-MS demonstrated improved the accuracy and precision for quantitative analysis of coal

Natural products in Glycyrrhiza glabra (licorice) rhizome imaged at the cellular level by atmospheric pressure matrix-assisted laser desorption/ionization tandem mass spectrometry imaging

DEFF Research Database (Denmark)

Li, Bin; Bhandari, Dhaka Ram; Janfelt, Christian

2014-01-01

The rhizome of Glycyrrhiza glabra (licorice) was analyzed by high-resolution mass spectrometry imaging and tandem mass spectrometry imaging. An atmospheric pressure matrix-assisted laser desorption/ionization imaging ion source was combined with an orbital trapping mass spectrometer in order to o...... and saponins in legume species, combing the spatially resolved chemical information with morphological details at the microscopic level. Furthermore, the technique offers a scheme capable of high-throughput profiling of metabolites in plant tissues....

Newborn screening by tandem mass spectrometry: ethical and social issues.

Science.gov (United States)

Avard, Denise; Vallance, Hilary; Greenberg, Cheryl; Potter, Beth

2007-01-01

Emerging technologies like Tandem Mass Spectrometry (TMS) enable multiple tests on a single blood sample and allow the expansion of Newborn Screening (NBS) to include various metabolic diseases. Introducing TMS for NBS raises important social and ethical questions: what are the criteria for adding disorders to screening panels? What evidence justifies expansion of screening? How can equity in NBS access and standards be ensured? How can policy standards be set, given the multiplicity of stakeholders? To address emerging issues, policy-makers, patient advocates, clinicians and researchers had a workshop during the 2005 Garrod Symposium. The participants received a summary of the discussion and understood the workshop's goal was to provide a basis for further discussion. This article contributes to this ongoing discussion. Several proposed recommendations assert the centrality of including social and ethical issues in the assessment of whether or not to introduce TMS. The article outlines five key recommendations for advancing the NBS agenda: national public health leadership; transparency; increased national consistency in NBS strategy, including minimum standards; collaboration between the federal and provincial/territorial governments and diverse stakeholders; and supporting research and/or programs based on effectiveness, which integrate ethical and social issues into assessment.

Tandem Mass Spectrometry Detection of Quorum Sensing Activity in Multidrug Resistant Clinical Isolate Acinetobacter baumannii

Directory of Open Access Journals (Sweden)

Kok-Gan Chan

2014-01-01

Full Text Available Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs. These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL and N-octanoyl-homoserine lactone (C8-HSL, was detected.

Quantification of citalopram or escitalopram and their demethylated metabolites in neonatal hair samples by liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Frison, Giampietro; Favretto, Donata; Vogliardi, Susanna; Terranova, Claudio; Ferrara, Santo Davide

2008-08-01

Citalopram and escitalopram are highly selective serotonin reuptake inhibitors widely used in the treatment of depression. They exhibit adverse drug reactions and side effects, however, and the development of specific methods for their determination is of great interest in clinical and forensic toxicology. A liquid chromatography-tandem mass spectrometry method has been developed and validated for the assay of citalopram, escitalopram, and their demethylated metabolites in 10-mg hair samples. The analytes were extracted by incubation in methanol and liquid/liquid extraction with diethyl ether/dichloromethane. Gradient elution on a narrow bore C18 column was realized using clomipramine-d3 as an internal standard. Positive ion electrospray ionization and tandem mass spectrometry determination by collision-induced dissociation were performed in an ion trap mass spectrometer. The method exhibited a linear range of 25 to 2000 pg/mg, a quantification limit of 25 pg/mg for all analytes, relative standard deviations in the range of 12.10 to 9.80 (intraassay), and 13.80 to 11.78 (interassay), and accuracies (as percent recovery of the spiked standards) in the range of 90% to 110%; it was applied to the determination of citalopram and escitalopram and their metabolites in hair samples of two newborns to document their in utero exposure to the drugs. The method proved suitable for neonatal hair analysis of citalopram or escitalopram and was applied to two real cases of gestational exposure.

[Simultaneous determination of 16 flavonoids in the ginkgo dietary supplement tea by high performance liquid chromatography-tandem mass spectrometry].

Science.gov (United States)

Jiang, Yalan; Huang, Fang; Wu, Fuhai; Wu, Huiqin; Huang, Xiaolan; Deng, Xin

2015-10-01

A method for the determination of 16 functional components of ginkgo dietary supplement tea such as catechin, vitexin, puerarin, isoflavoues aglycone, silymarin, quercetin, luteolin, apigenin, naringenin, hesperitin dihydrochalcone, kaempferol, hesperitin, isorhamnetin, baicalein, nobiletin and tangeretin by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was proposed. The conditions of chromatography and mass spectrometry were optimized. The 16 flavonoids were separated on a C18 chromatographic column with acetonitrile and water (additional 0.1% formic acid) as mobile phases under gradient elution at a flow rate of 0.25 mL/min. The determination was conducted by tandem mass spectrometry in positive ESI mode under multiple reaction monitoring (MRM) mode. Good linearities for all the compounds, with correlation coefficients over 0.996, were acquired. The recoveries were in the range of 70.9% to 100.0% (n = 6), while the relative standard deviations (RSDs) were less than 10%. The results showed that the nine flavonoids, which were kaempferol, quercetin, hesperitin, vitexin, luteolin, catechin, apigenin, naringenin and isorhamnetin, were higher in contents among the 16 flavonoids in real samples, and they constituted up to 99.6% of the total flavonoids. The contents of these nine flavonoids can be considered as the quality control index of the ginkgo dietary supplement tea. The method proved to be rapid, selective, sensitive and stable, and it can be applied to control the quality of the ginkgo dietary supplement tea.

Determination of salbutamol and salbutamol glucuronide in human urine by means of liquid chromatography-tandem mass spectrometry

DEFF Research Database (Denmark)

Mareck, Ute; Guddat, Sven; Schwenke, Anne

2012-01-01

The determination of salbutamol and its glucuronide in human urine following the inhalative and oral administration of therapeutic doses of salbutamol preparations was performed by means of direct urine injection utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) and employing d(3...... glucuronide values between 8 and 15 ng/ml. The approach enabled the rapid determination of salbutamol and its glucuronic acid conjugate in human urine and represents an alternative to existing procedures since time-consuming hydrolysis or derivatization steps were omitted. Moreover, the excretion...

Rapid Identification of Steroidal Saponins in Trillium tschonoskii Maxim by Ultraperformance Liquid Chromatography Coupled to Electrospray Ionisation Quadrupole Time-of-Flight Tandem Mass Spectrometry.

Science.gov (United States)

Gao, Xin; Sun, Wenjun; Fu, Qiang; Niu, Xiaofeng

2015-01-01

Steroidal saponins in Trillium tschonoskii Maxim have many biological activities, including immunological regulation and anti-tumour. Comprehensive ingredient identification is critical for understanding its pharmacological mechanism and establishing quality control protocols. However, it is a challenging problem because of the complexity of steroidal saponins. To develop a UPLC-MS method for identifying and characterising steroidal saponins in the root and rhizome of T. tschonoskii. Methanolic extracts of T. tschonoskii were analysed by using ultraperformance liquid chromatography coupled to electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI/QTOF/MS). The UPLC experiments were performed by means of a reversed-phase C18 -column and a binary mobile phase system consisting of water and acetonitrile with formic acid under gradient elution conditions. For the UPLC-MS measurements, positive and negative ion modes were used in order to obtain better tandem mass spectra and high-resolution mass spectra. Based on retention times, accurate mass and mass spectrometric fragmentation, a total of 31 saponins distributed over eight steroidal aglycone skeletons were identified or tentatively elucidated from T. tschonoskii. The UPLC-ESI/QTOF/MS method has proven to be a powerful tool for rapid identification of steroidal saponins in T. tschonoskii without tedious and time-consuming isolation of pure constituents. Copyright © 2015 John Wiley & Sons, Ltd.

Identification and Quantification of the Major Constituents in Egyptian Carob Extract by Liquid Chromatography?Electrospray Ionization-Tandem Mass Spectrometry

OpenAIRE

Owis, Asmaa Ibrahim; El-Naggar, El-Motaz Bellah

2016-01-01

Background: Carob - Ceratonia siliqua L., commonly known as St John's-bread or locust bean, family Fabaceae - is one of the most useful native Mediterranean trees. There is no data about the chromatography methods performed by high performance liquid chromatography (HPLC) for determining polyphenols in Egyptian carob pods. Objective: To establish a sensitive and specific liquid chromatography?electrospray ionization (ESI)-tandem mass spectrometry (MSn) methodology for the identification of th...

Isobaric Expansion Engines: New Opportunities in Energy Conversion for Heat Engines, Pumps and Compressors

Directory of Open Access Journals (Sweden)

Maxim Glushenkov

2018-01-01

Full Text Available Isobaric expansion (IE engines are a very uncommon type of heat-to-mechanical-power converters, radically different from all well-known heat engines. Useful work is extracted during an isobaric expansion process, i.e., without a polytropic gas/vapour expansion accompanied by a pressure decrease typical of state-of-the-art piston engines, turbines, etc. This distinctive feature permits isobaric expansion machines to serve as very simple and inexpensive heat-driven pumps and compressors as well as heat-to-shaft-power converters with desired speed/torque. Commercial application of such machines, however, is scarce, mainly due to a low efficiency. This article aims to revive the long-known concept by proposing important modifications to make IE machines competitive and cost-effective alternatives to state-of-the-art heat conversion technologies. Experimental and theoretical results supporting the isobaric expansion technology are presented and promising potential applications, including emerging power generation methods, are discussed. It is shown that dense working fluids with high thermal expansion at high process temperature and low compressibility at low temperature make it possible to operate with reasonable thermal efficiencies at ultra-low heat source temperatures (70–100 °C. Regeneration/recuperation of heat can increase the efficiency notably and extend the area of application of these machines to higher heat source temperatures. For heat source temperatures of 200–600 °C, the efficiency of these machines can reach 20–50% thus making them a flexible, economical and energy efficient alternative to many today’s power generation technologies, first of all organic Rankine cycle (ORC.

Performance of isobaric and isotopic labeling in quantitative plant proteomics

DEFF Research Database (Denmark)

Nogueira, Fábio C S; Palmisano, Giuseppe; Schwämmle, Veit

2012-01-01

, and quantitation. In the present work, we have used LC-MS to compare an isotopic (ICPL) and isobaric (iTRAQ) chemical labeling technique to quantify proteins in the endosperm of Ricinus communis seeds at three developmental stages (IV, VI, and X). Endosperm proteins of each stage were trypsin-digested in...

EPA CRL MS014: Analysis of Aldicarb, Bromadiolone, Carbofuran, Oxamyl and Methomyl in Water by Multiple Reaction Monitoring Liquid Chromatography / Tandem Mass Spectrometry (LC/MS/MS)

Science.gov (United States)

Method MS014 describes procedures for solvent extraction of aldicarb, bromadiolone, carbofuran, oxamyl and methomyl from water samples, followed by analysis using liquid chromatography tandem mass spectrometry (LC-MS-MS).

The inclusion of ADA-SCID in expanded newborn screening by tandem mass spectrometry.

Science.gov (United States)

la Marca, Giancarlo; Giocaliere, Elisa; Malvagia, Sabrina; Funghini, Silvia; Ombrone, Daniela; Della Bona, Maria Luisa; Canessa, Clementina; Lippi, Francesca; Romano, Francesca; Guerrini, Renzo; Resti, Massimo; Azzari, Chiara

2014-01-01

Severe combined immunodeficiency due to adenosine-deaminase defect (ADA-SCID) is usually deadly in childhood because of severe recurrent infections. When clinical diagnosis is done, permanent damages due to infections or metabolite accumulation are often present. Gene therapy, bone marrow transplantation or enzyme replacement therapy may be effective if started early. The aim of this study was to set-up a robust method suitable for screening with a minimized preparation process and with inexpensive running costs, for diagnosing ADA-SCID by tandem mass spectrometry. ADA-SCID satisfies all the criteria for inclusion in a newborn screening program. We describe a protocol revised to incorporate adenosine and 2-deoxyadenosine testing into an expanded newborn screening program. We assessed the effectiveness of this approach testing dried blood spots from 4 genetically confirmed early-onset and 5 delayed-onset ADA-SCID patients. Reference values were established on 50,000 healthy newborns (deoxyadenosine ADA) gene. The results show that the method having great simplicity, low cost and low process preparations can be fully applicable to a mass screening program. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of olanzapine in whole blood using simple protein precipitation and liquid chromatography-tandem mass spectrometry

DEFF Research Database (Denmark)

Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

2009-01-01

A simple, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of the antipsychotic drug olanzapine in whole blood using dibenzepine as internal standard (IS). After acidic methanol-induced protein precipitation......, and stability. The absolute recovery obtained was 103% for olanzapine and 68% for IS. An LOQ of 0.005 mg/kg olanzapine in whole blood was achieved. Inter- and intraday precision were less than 11% within concentrations from 0.01 to 0.50 mg/kg, and the accuracy ranged from 85 to 115%. The method was subsequently...

Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2016-04-01

In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polarization phenomena in isobar production by a weak neutral current

International Nuclear Information System (INIS)

Esajbegyan, S.V.; Matinyan, S.G.

1977-01-01

Polarization phenomen connected with weak neutral currents producing the isobar in the lepton-nucleon scattering are considered. It is shown that measurement of the angular distribution of π mesons so as to detect also the longitudinally polarized decay nucleon can provide usefull information about validity of various models including a weak neutral current

{sup 36}Cl exposure dating with a 3-MV tandem

Energy Technology Data Exchange (ETDEWEB)

Steier, Peter, E-mail: peter.steier@univie.ac.a [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Forstner, Oliver; Golser, Robin; Kutschera, Walter; Martschini, Martin [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Merchel, Silke [CEREGE, CNRS-IRD-Universite Aix-Marseille, Europole Mediterraneen de L' Arbois, 13545 Aix-en-Provence (France); Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Orlowski, Tobias; Priller, Alfred [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Vockenhuber, Christof [Forschungszentrum Dresden-Rossendorf, D-01314 Dresden (Germany); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland); Wallner, Anton [VERA Laboratory, Fakultaet fuer Physik - Isotopenforschung, Universitaet Wien, Waehringer Strasse 17, A-1090 Wien (Austria); HPK H 31, Institut fuer Teilchenphysik, ETH Zuerich, Schafmattstr. 20 CH-8093 Zuerich (Switzerland)

2010-04-15

{sup 36}Cl AMS measurements at natural isotopic concentrations have yet been performed only at tandem accelerators with 5 MV terminal voltage or beyond. We have developed a method to detect {sup 36}Cl at natural terrestrial isotopic concentrations with a 3-MV system, operated above specifications at 3.5 MV. An effective separation was obtained with an optimized split-anode ionization chamber design (adopted from the ETH/PSI Zurich AMS group), providing a suppression factor of up to 30,000 for the interfering isobar {sup 36}S. Despite the good separation, a relatively high sulfur output from the ion source ({sup 36}S{sup -}/{sup 35}Cl{sup -} approx 4 x 10{sup -10} for samples prepared from chemically pure reagents), and a possibly cross contamination resulted in a background corresponding to {sup 36}Cl/Cl approx 3 x 10{sup -14}. The method was applied to samples containing between 10{sup 5} and 10{sup 6} atoms {sup 36}Cl/g rock from sites in Italy and Iran, which were already investigated by other laboratories for surface exposure dating. The {sup 36}Cl/Cl ratios in the range from 2 x 10{sup -13} to 5 x 10{sup -12} show a generally good agreement with the previous results. These first measurements demonstrate that also 3-MV tandems, constituting the majority of dedicated AMS facilities, are capable of {sup 36}Cl exposure dating, which is presently the domain of larger facilities.

Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Analysis of Fosetyl-Aluminum in Airborne Particulate Matter

Directory of Open Access Journals (Sweden)

Francesca Buiarelli

2018-01-01

Full Text Available Fosetyl-aluminum is a synthetic fungicide administered to plants especially to prevent diseases caused by the members of the Peronosporales and several Phytophthora species. Herein, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS method to analyze residues of fosetyl-A1 in air particulate matter. This study was performed in perspective of an exposure assessment of this substance of health concern in environments where high levels of fosetly-Al, relatively to airborne particulate matter, can be found after spraying it. The cleanup procedure of the analyte, from sampled filters of atmospheric particulate matter, was optimized using a Strata X solid-phase extraction cartridge, after accelerated extraction by using water. The chromatographic separation was achieved using a polymeric column based on hydrophilic interaction in step elution with water/acetonitrile, whereas the mass spectrometric detection was performed in negative electrospray ionization. The proposed method resulted to be a simple, fast, and suitable method for confirmation purposes.

Proteomic profiling of human pleural effusion using two-dimensional nano liquid chromatography tandem mass spectrometry.

Science.gov (United States)

Tyan, Yu-Chang; Wu, Hsin-Yi; Lai, Wu-Wei; Su, Wu-Chou; Liao, Pao-Chi

2005-01-01

Pleural effusion, an accumulation of pleural fluid, contains proteins originated from plasma filtrate and, especially when tissues are damaged, parenchyma interstitial spaces of lungs and/or other organs. This study details protein profiles in human pleural effusion from 43 lung adenocarcinoma patients by a two-dimensional nano-high performance liquid chromatography electrospray ionization tandem mass spectrometry (2D nano-HPLC-ESI-MS/MS) system. The experimental results revealed the identification of 1415 unique proteins from human pleural effusion. Among these 124 proteins identified with higher confidence levels, some proteins have not been reported in plasma and may represent proteins specifically present in pleural effusion. These proteins are valuable for mass identification of differentially expressed proteins involved in proteomics database and screening biomarker to further study in human lung adenocarcinoma. The significance of the use of proteomics analysis of human pleural fluid for the search of new lung cancer marker proteins, and for their simultaneous display and analysis in patients suffering from lung disorders has been examined.

Recent advances of liquid chromatography-(tandem) mass spectrometry in clinical and forensic toxicology - An update.

Science.gov (United States)

Remane, Daniela; Wissenbach, Dirk K; Peters, Frank T

2016-09-01

Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) is a well-established and widely used technique in clinical and forensic toxicology as well as doping control especially for quantitative analysis. In recent years, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in biological matrices have been developed. Such methods have proven particularly useful for analysis of so-called new psychoactive substances that have appeared on recreational drug markets throughout the world. Moreover, the evolvement of high resolution MS techniques and the development of data-independent detection modes have opened new possibilities for applications of LC-(MS/MS) in systematic toxicological screening analysis in the so called general unknown setting. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2010. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

End-group characterisation of poly(propylene glycol)s by means of electrospray ionisation-tandem mass spectrometry (ESI-MS/MS).

Science.gov (United States)

Jackson, Anthony T; Slade, Susan E; Thalassinos, Konstantinos; Scrivens, James H

2008-10-01

The end-group functionalisation of a series of poly(propylene glycol)s has been characterised by means of electrospray ionisation-tandem mass spectrometry (ESI-MS/MS). A series of peaks with mass-to-charge ratios that are close to that of the precursor ion were used to generate information on the end-group functionalities of the poly(propylene glycol)s. Fragment ions resulting from losses of both of the end groups were noted from some of the samples. An example is presented of how software can be used to significantly reduce the length of time involved in data interpretation (which is typically the most time-consuming part of the analysis).

Improved Tandem Measurement Techniques for Aerosol Particle Analysis

Science.gov (United States)

Rawat, Vivek Kumar

Non-spherical, chemically inhomogeneous (complex) nanoparticles are encountered in a number of natural and engineered environments, including combustion systems (which produces highly non-spherical aggregates), reactors used in gas-phase materials synthesis of doped or multicomponent materials, and in ambient air. These nanoparticles are often highly diverse in size, composition and shape, and hence require determination of property distribution functions for accurate characterization. This thesis focuses on development of tandem mobility-mass measurement techniques coupled with appropriate data inversion routines to facilitate measurement of two dimensional size-mass distribution functions while correcting for the non-idealities of the instruments. Chapter 1 provides the detailed background and motivation for the studies performed in this thesis. In chapter 2, the development of an inversion routine is described which is employed to determine two dimensional size-mass distribution functions from Differential Mobility Analyzer-Aerosol Particle Mass analyzer tandem measurements. Chapter 3 demonstrates the application of the two dimensional distribution function to compute cumulative mass distribution function and also evaluates the validity of this technique by comparing the calculated total mass concentrations to measured values for a variety of aerosols. In Chapter 4, this tandem measurement technique with the inversion routine is employed to analyze colloidal suspensions. Chapter 5 focuses on application of a transverse modulation ion mobility spectrometer coupled with a mass spectrometer to study the effect of vapor dopants on the mobility shifts of sub 2 nm peptide ion clusters. These mobility shifts are then compared to models based on vapor uptake theories. Finally, in Chapter 6, a conclusion of all the studies performed in this thesis is provided and future avenues of research are discussed.

Advanced Analysis of Isobaric Heat Capacities by Mathematical Gnostics

Czech Academy of Sciences Publication Activity Database

Wagner, Zdeněk; Bendová, Magdalena; Rotrekl, Jan; Velíšek, Petr; Storch, Jan; Uchytil, Petr; Setničková, Kateřina; Řezníčková Čermáková, Jiřina

2017-01-01

Roč. 46, 9-10 (2017), s. 1836-1853 ISSN 0095-9782. [International Symposium on Solubility Phenomena and Related Equilibrium Processes. Geneva, 24.07.2016-29.07.2016] R&D Projects: GA MŠk LD14090 Institutional support: RVO:67985858 Keywords : isobaric heat capacity * ionic liquids * mathematical gnostics Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.342, year: 2016

[Low dose isobaric, hyperbaric, or hypobaric bupivacaine for unilateral spinal anesthesia.].

Science.gov (United States)

Imbelloni, Luiz Eduardo; Beato, Lúcia; Gouveia, Marildo A; Cordeiro, José Antônio

2007-06-01

Unilateral spinal anesthesia has its advantages, especially in patients undergoing outpatient basis surgeries. Low dose, slow speed of administration, and the lateral positioning make easier the unilateral distribution in spinal anesthesia. Isobaric, hyperbaric, and hypobaric solutions of bupivacaine were compared in the unilateral spinal anesthesia in patients undergoing outpatient basis orthopedic surgeries. One hundred and fifty patients were randomly divided in three groups to receive 5 mg of 0.5% isobaric bupivacaine (Iso Group), 5 mg of 0.5% hyperbaric bupivacaine (Hyper Group), or 5 mg of 0.15% hypobaric bupivacaine (Hypo Group). The solutions were administered in the L3-L4 space with the patient in the lateral decubitus and remaining in this position for 20 minutes. Sensitive anesthesia was evaluated by the pin prick test. Motor blockade was determined by the modified Bromage scale. Both blockades were compared with the opposite side and among themselves. There was a significant difference between the side of the surgery and the opposite side in all three groups at 20 minutes, but the frequency of unilateral spinal anesthesia was greater with the hyperbaric and hypobaric solutions. Sensitive and motor blockades were observed in 14 patients in the Iso Group, 38 patients in the Hyper Group, and 40 patients in the Hypo Group. Patients did not develop any hemodynamic changes. Postpuncture headache and transitory neurological symptoms were not observed. Spinal anesthesia with hypobaric and hyperbaric solutions present a higher frequency of unilateral anesthesia. After 20 minutes, isobaric bupivacaine mobilized into cerebrospinal fluid (CSF) resulted in unilateral spinal anesthesia in only 28% of the patients.

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

Science.gov (United States)

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

Simultaneous Determination of 25 Common Pharmaceuticals in Whole Blood Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

DEFF Research Database (Denmark)

Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

2012-01-01

An ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of 25 common pharmaceuticals in whole blood. The selected pharmaceuticals represent the most frequently detected drugs in our forensic laboratory with basic properties....../kg depending on the analyte. A good linear behavior was achieved for all analytes in the range from LOQ to 1.0 or 2.0 mg/kg blood. The absolute recoveries were between 55-87% for all compounds except norfluoxetine (44%). The method showed acceptable precision and accuracy for almost all analytes. Only unstable...

Self consistent and covariant propagation of pions, nucleon and isobar resonances in cold nuclear matter

International Nuclear Information System (INIS)

Korpa, C.L.; Lutz, M.F.M.; Technische Univ. Darmstadt

2003-06-01

We evaluate the in-medium spectral functions for pions, nucleon and isobar resonances in a self consistent and covariant manner. The calculations are based on a recently developed formulation which leads to predictions in terms of the pion-nucleon scattering phase shifts and a set of Migdal parameters describing important short range correlation effects. We do not observe any significant softening of pion modes if we insist on reasonable isobar resonance properties but predict a considerable broadening of the N(1440) and N(1520) resonances in nuclear matter. (orig.)

Acrylamide levels in Finnish foodstuffs analysed with liquid chromatography tandem mass spectrometry.

Science.gov (United States)

Eerola, Susanna; Hollebekkers, Koen; Hallikainen, Anja; Peltonen, Kimmo

2007-02-01

Sample clean-up and HPLC with tandem mass spectrometric detection (LC-MS/MS) was validated for the routine analysis of acrylamide in various foodstuffs. The method used proved to be reliable and the detection limit for routine monitoring was sensitive enough for foods and drinks (38 microg/kg for foods and 5 microg/L for drinks). The RSDs for repeatability and day-to-day variation were below 15% in all food matrices. Two hundred and one samples which included more than 30 different types of food and foods manufactured and prepared in various ways were analysed. The main types of food analysed were potato and cereal-based foods, processed foods (pizza, minced beef meat, meat balls, chicken nuggets, potato-ham casserole and fried bacon) and coffee. Acrylamide was detected at levels, ranging from nondetectable to 1480 microg/kg level in solid food, with crisp bread exhibiting the highest levels. In drinks, the highest value (29 microg/L) was found in regular coffee drinks.

Determination of dapsone in meat and milk by liquid chromatography tandem mass spectrometry

International Nuclear Information System (INIS)

Hadjigeorgiou, M.; Papachrysostomou, Ch.; Theodorou, Z.; Kanari, P.; Constantinou, S.

2009-01-01

Within the EU the use of dapsone (4,4-diaminodiphenylsulfone) is prohibited in food-producing animals and consequently it's included in the Annex IV of the Directive 90/2377/EC. A quantitative confirmatory method has been developed and validated according to the criteria defined in the Commission Decision 2002/657/EC, for the determination of dapsone in meat and milk. Samples, after homogenization in alkaline conditions and organic solvent extraction, were purified on silica gel solid phase extraction cartridges. The eluate was evaporated and redissolved in mobile phase and was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionisation (ESI) using deuterium labelled Sulphadimidine-d7 as internal standard. The calculated value for, decision limit, CCα is 0.12 μg kg -1 , and the detection capability; CCβ value is 0.16 μg kg -1

Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

Science.gov (United States)

Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

2014-11-01

A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of the isobaric compounds propanol, acetic acid and methyl formate in humid air and breath by selected ion flow tube mass spectrometry, SIFT-MS

Czech Academy of Sciences Publication Activity Database

Pysanenko, A.; Španěl, Patrik; Smith, D.

2009-01-01

Roč. 285, 1-2 (2009), s. 42-48 ISSN 1387-3806 R&D Projects: GA ČR GA203/09/0256; GA ČR GA202/09/0800 Institutional research plan: CEZ:AV0Z40400503 Keywords : SIFT-MS * isobaric compound * propanol * acetic acid Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.117, year: 2009

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

Science.gov (United States)

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

2007-10-15

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

Detection of nicotine as an indicator of tobacco smoke by direct analysis in real time (DART) tandem mass spectrometry

Science.gov (United States)

Kuki, Ákos; Nagy, Lajos; Nagy, Tibor; Zsuga, Miklós; Kéki, Sándor

2015-01-01

The residual tobacco smoke contamination (thirdhand smoke, THS) on the clothes of a smoker was examined by direct analysis in real time (DART) mass spectrometry. DART-MS enabled sensitive and selective analysis of nicotine as the indicator of tobacco smoke pollution. Tandem mass spectrometric (MS/MS) experiments were also performed to confirm the identification of nicotine. Transferred thirdhand smoke originated from the fingers of a smoker onto other objects was also detected by DART mass spectrometry. DART-MS/MS was utilized for monitoring the secondhand tobacco smoke (SHS) in the air of the laboratory using nicotine as an indicator. To the best of our knowledge, this is the first report on the application of DART-MS and DART-MS/MS to the detection of thirdhand smoke and to the monitoring of secondhand smoke.

High-Resolution Liquid Chromatography Tandem Mass Spectrometry Enables Large Scale Molecular Characterization of Dissolved Organic Matter

Directory of Open Access Journals (Sweden)

Daniel Petras

2017-12-01

Full Text Available Dissolved organic matter (DOM is arguably one of the most complex exometabolomes on earth, and is comprised of thousands of compounds, that together contribute more than 600 × 1015 g carbon. This reservoir is primarily the product of interactions between the upper ocean's microbial food web, yet abiotic processes that occur over millennia have also modified many of its molecules. The compounds within this reservoir play important roles in determining the rate and extent of element exchange between inorganic reservoirs and the marine biosphere, while also mediating microbe-microbe interactions. As such, there has been a widespread effort to characterize DOM using high-resolution analytical methods including nuclear magnetic resonance spectroscopy (NMR and mass spectrometry (MS. To date, molecular information in DOM has been primarily obtained through calculated molecular formulas from exact mass. This approach has the advantage of being non-targeted, accessing the inherent complexity of DOM. Molecular structures are however still elusive and the most commonly used instruments are costly. More recently, tandem mass spectrometry has been employed to more precisely identify DOM components through comparison to library mass spectra. Here we describe a data acquisition and analysis workflow that expands the repertoire of high-resolution analytical approaches available to access the complexity of DOM molecules that are amenable to electrospray ionization (ESI MS. We couple liquid chromatographic separation with tandem MS (LC-MS/MS and a data analysis pipeline, that integrates peak extraction from extracted ion chromatograms (XIC, molecular formula calculation and molecular networking. This provides more precise structural characterization. Although only around 1% of detectable DOM compounds can be annotated through publicly available spectral libraries, community-wide participation in populating and annotating DOM datasets could rapidly increase the

Characterization of Proanthocyanidins from Parkia biglobosa (Jacq. G. Don. (Fabaceae by Flow Injection Analysis — Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry

Directory of Open Access Journals (Sweden)

Wagner Vilegas

2013-03-01

Full Text Available The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

Isobaric intermediate states in proton-nucleus elastic scattering

International Nuclear Information System (INIS)

Auger, J.P.; Lazard, C.; Lombard, R.J.

1981-05-01

The effects of the propagation of isobaric nucleon states in the intermediate steps of the multiple scattering have been studied with application on the proton- 4 He elastic scattering at 1 GeV. The calculations are performed in the Glauber model and results are given for the differential cross section, the polarization and the spin rotation parameter. In our conclusions we stress the large cancellations observed between terms of various orders and the great sensitivity of the effects to the nucleon-nucleon amplitudes

Analysis of bromate in drinking water using liquid chromatography-tandem mass spectrometry without sample pretreatment.

Science.gov (United States)

Kosaka, Koji; Asami, Mari; Takei, Kanako; Akiba, Michihiro

2011-01-01

An analytical method for determining bromate in drinking water was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The (18)O-enriched bromate was used as an internal standard. The limit of quantification (LOQ) of bromate was 0.2 µg/L. The peak of bromate was separated from those of coexisting ions (i.e., chloride, nitrate and sulfate). The relative and absolute recoveries of bromate in two drinking water samples and in a synthesized ion solution (100 mg/L chloride, 10 mg N/L nitrate, and 100 mg/L sulfate) were 99-105 and 94-105%, respectively. Bromate concentrations in 11 drinking water samples determined by LC-MS/MS were water without sample pretreatment.

JAERI tandem-accelerator and tandem-booster

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Tadashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

In 1982, aiming at the new development of atomic energy research, the tandem accelerator of Japan Atomic Energy Research Institute (JAERI) was installed. In fiscal year 1993, the superconducting boosters which can increase the ion energy by up to 4 times were added, and the research in the region below 1000 MeV became possible. Those are electrostatic type accelerators which are easy to be used especially in basic research field, and are useful for future research. The tandem accelerator has been operated while maintaining the first class performance as the accelerator for various kinds of heavy ion beam. It has the special shape among electrostatic type accelerators, and is excellent in the easiness of control and stability. The main particulars of the tandem accelerator are shown. As for the ion sources of the tandem accelerator, three cesium sputter type ion sources are installed on two high voltage stands. The kinds of the ions which can be accelerated are mainly negative ions. As the improvement, electron cyclotron resonance (ECR) ion sources are expected to be adopted. As for the tandem boosters, the 1/4 wavelength type resonance hollow cylinder was adopted. The constitution of the tandem boosters is explained. The way of utilizing the tandem accelerator system and the aim for hereafter are reported. (K.I.)

Precise measurements of mass of Rb isotopes with A=91-97

International Nuclear Information System (INIS)

Alkhazov, G.D.; Belyaev, B.N.; Domkin, V.D.; Korobulin, Yu.G.; Lukashevich, V.V.; Mukhin, V.S.; AN SSSR, Leningrad

1989-01-01

A new scheme of the experiment on measuring the short-living nuclide atom masses, based on applying the isobar doublet method for mass scale gauging, is proposed. Results of measuring masses of Rb isotope atom with A=91-97, performed using a prism mass-spectrometer on line with the LiYaF mass-separator and synchrocyclotron with 30-80 keV error are presented

Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Owens, J; Hok, S; Alcaraz, A; Koester, C

2008-11-13

Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

Quantitative Analysis of Tetramethylenedisulfotetramine ('Tetramine') Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

International Nuclear Information System (INIS)

Owens, J.; Hok, S.; Alcaraz, A.; Koester, C.

2008-01-01

Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD 50 = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 (micro)g/mL by LC/MS/MS versus 0.15 (micro)g/mL for GC/MS. Fortifications of the beverages at 2.5 (micro)g/mL and 0.25 (micro)g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

Tandem mass spectrometry, but not T-cell receptor excision circle analysis, identifies newborns with late-onset adenosine deaminase deficiency.

Science.gov (United States)

la Marca, Giancarlo; Canessa, Clementina; Giocaliere, Elisa; Romano, Francesca; Duse, Marzia; Malvagia, Sabrina; Lippi, Francesca; Funghini, Silvia; Bianchi, Leila; Della Bona, Maria Luisa; Valleriani, Claudia; Ombrone, Daniela; Moriondo, Maria; Villanelli, Fabio; Speckmann, Carsten; Adams, Stuart; Gaspar, Bobby H; Hershfield, Michael; Santisteban, Ines; Fairbanks, Lynette; Ragusa, Giovanni; Resti, Massimo; de Martino, Maurizio; Guerrini, Renzo; Azzari, Chiara

2013-06-01

Adenosine deaminase (ADA)-severe combined immunodeficiency (SCID) is caused by genetic variants that disrupt the function of ADA. In its early-onset form, it is rapidly fatal to infants. Delayed or late-onset ADA-SCID is characterized by insidious progressive immunodeficiency that leads to permanent organ damage or death. Quantification of T-cell receptor excision circles (TRECs) or tandem mass spectrometry (tandem-MS) analysis of dried blood spots (DBSs) collected at birth can identify newborns with early-onset ADA-SCID and are used in screening programs. However, it is not clear whether these analyses can identify newborns who will have delayed or late-onset ADA-SCID before symptoms appear. We performed a retrospective study to evaluate whether tandem-MS and quantitative TREC analyses of DBSs could identify newborns who had delayed-onset ADA-SCID later in life. We tested stored DBSs collected at birth from 3 patients with delayed-onset ADA-SCID using tandem-MS (PCT EP2010/070517) to evaluate levels of adenosine and 2'-deoxyadenosine and real-time PCR to quantify TREC levels. We also analyzed DBSs from 3 newborns with early-onset ADA-SCID and 2 healthy newborn carriers of ADA deficiency. The DBSs taken at birth from the 3 patients with delayed-onset ADA-SCID had adenosine levels of 10, 25, and 19 μmol/L (normal value, <1.5 μmol/L) and 2'-deoxyadenosine levels of 0.7, 2.7, and 2.4 μmol/L (normal value, <0.07 μmol/L); the mean levels of adenosine and 2'-deoxyadenosine were respectively 12.0- and 27.6-fold higher than normal values. DBSs taken at birth from all 3 patients with delayed-onset ADA deficiency had normal TREC levels, but TRECs were undetectable in blood samples taken from the same patients at the time of diagnosis. Tandem-MS but not TREC quantification identifies newborns with delayed- or late-onset ADA deficiency. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Densities, viscosities, and isobaric heat capacities of the system (1-butanol + cyclohexane) at high pressures

International Nuclear Information System (INIS)

Torín-Ollarves, Geraldine A.; Martín, M. Carmen; Chamorro, César R.; Segovia, José J.

2014-01-01

Highlights: • The densities of cyclohexane and its mixtures with 1-butanol were measured. • The excess molar volumes were calculated and correlated. • The viscosities were measured at atmospheric pressure. • The isobaric heat capacities were measured at p = (0.1 to 25) MPa at T = (293.15 and 313.15) K. • A positive deviation from the ideal behavior is observed. - Abstract: The cyclohexane and the system of 1-butanol + cyclohexane have been characterized using densities, viscosities and isobaric heat capacities measurements. For that, the densities were measured in a high-pressure vibrating tube densimeter at five temperatures from (293.15 to 333.15) K and pressures up to 100 MPa. The measurements were correlated with the empirical Tamman–Tait equation. Moreover, the isobaric heat capacities of the binary system were measured in a high-pressure automated flow calorimeter at T = (293.15 and 313.15) K and pressures up to 25 MPa for pure cyclohexane and in admixture with 1-butanol. The excess molar heat capacities were assessed for the mixture and a positive deviation from the ideality was obtained, except for a small part in the region rich in alkanol. The viscosity measurements were carried out, at the calorimeter conditions, for correcting the experimental values of isobaric heat capacities due to friction along the tube. The viscosity was measured at atmospheric pressure in a Stabinger Anton Paar SVM 3000 viscometer in the temperature range of (293.15 to 333.15) K for cyclohexane and the mixtures. At high pressure, the viscosities were estimated using Lucas method

A new liquid chromatography - tandem mass spectrometry method using atmospheric pressure photo ionization for the simultaneous determination of azaarenes and azaarones in Dutch river sediments

NARCIS (Netherlands)

Brulik, J.; Simek, Z.; de Voogt, P.

2013-01-01

A new method for the analysis of azaarenes and their degradation products (azaarones) was developed, optimized and validated using liquid chromatography coupled with atmospheric pressure photo ionization tandem mass spectrometric detection (LC-APPI/MS/MS). Seventeen compounds including 4 PAHs

Precision Mass Measurement of Argon Isotopes

CERN Multimedia

Lunney, D

2002-01-01

% IS388\\\\ \\\\ A precision mass measurement of the neutron-deficient isotopes $^{32,33,34}$Ar is proposed. Mass values of these isotopes are of importance for: a) a stringent test of the Isobaric-Multiplet- Mass-Equation, b) a verification of the correctness of calculated charge-dependent corrections as used in super-allowed $\\beta$- decay studies aiming at a test of the CVC hypothesis, and c) the determination of the kinematics in electron-neutrino correlation experiments searching for scalar currents in weak interaction. The measurements will be carried out with the ISOLTRAP Penning trap mass spectrometer.

Laser desorption/ionization mass spectrometry for direct profiling and imaging of small molecules from raw biological materials

Energy Technology Data Exchange (ETDEWEB)

Cha, Sangwon [Iowa State Univ., Ames, IA (United States)

2008-01-01

Matrix-assisted laser desorption/ionization(MALDI) mass spectrometry(MS) has been widely used for analysis of biological molecules, especially macromolecules such as proteins. However, MALDI MS has a problem in small molecule (less than 1 kDa) analysis because of the signal saturation by organic matrixes in the low mass region. In imaging MS (IMS), inhomogeneous surface formation due to the co-crystallization process by organic MALDI matrixes limits the spatial resolution of the mass spectral image. Therefore, to make laser desorption/ionization (LDI) MS more suitable for mass spectral profiling and imaging of small molecules directly from raw biological tissues, LDI MS protocols with various alternative assisting materials were developed and applied to many biological systems of interest. Colloidal graphite was used as a matrix for IMS of small molecules for the first time and methodologies for analyses of small metabolites in rat brain tissues, fruits, and plant tissues were developed. With rat brain tissues, the signal enhancement for cerebroside species by colloidal graphite was observed and images of cerebrosides were successfully generated by IMS. In addition, separation of isobaric lipid ions was performed by imaging tandem MS. Directly from Arabidopsis flowers, flavonoids were successfully profiled and heterogeneous distribution of flavonoids in petals was observed for the first time by graphite-assisted LDI(GALDI) IMS.

Self-consistent description of isobaric 0+ states taking the one-particle continuum into account exactly

International Nuclear Information System (INIS)

Pyatov, N.I.; Salamov, D.I.; Fayans, S.A.

1981-01-01

The properties of discrete and resonance isobaric 0 + states of nuclei are studied within the framework of a self-consistent approach. The equations for the charge-exchange effective field are solved in the coordinate representation taking the one-particle continuum into account exactly. Microscopic estimates of the analog-state energies and the matrix elements, transition densities, and strength functions of the isospin-allowed and forbidden Fermi transitions are obtained together with the values of the isospin admixtures in the ground states of the parent nuclei and their analogs. The escape widths of the isobaric resonances are also discussed

Detection of Stimulants and Narcotics by Liquid Chromatography-Tandem Mass Spectrometry and Gas Chromatography-Mass Spectrometry for Sports Doping Control.

Science.gov (United States)

Ahrens, Brian D; Kucherova, Yulia; Butch, Anthony W

2016-01-01

Sports drug testing laboratories are required to detect several classes of compounds that are prohibited at all times, which include anabolic agents, peptide hormones, growth factors, beta-2 agonists, hormones and metabolic modulators, and diuretics/masking agents. Other classes of compounds such as stimulants, narcotics, cannabinoids, and glucocorticoids are also prohibited, but only when an athlete is in competition. A single class of compounds can contain a large number of prohibited substances and all of the compounds should be detected by the testing procedure. Since there are almost 70 stimulants on the prohibited list it can be a challenge to develop a single screening method that will optimally detect all the compounds. We describe a combined liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) testing method for detection of all the stimulants and narcotics on the World Anti-Doping Agency prohibited list. Urine for LC-MS/MS testing does not require sample pretreatment and is a direct dilute and shoot method. Urine samples for the GC-MS method require a liquid-liquid extraction followed by derivatization with trifluoroacetic anhydride.

Authentication of Closely Related Fish and Derived Fish Products Using Tandem Mass Spectrometry and Spectral Library Matching.

Science.gov (United States)

Nessen, Merel A; van der Zwaan, Dennis J; Grevers, Sander; Dalebout, Hans; Staats, Martijn; Kok, Esther; Palmblad, Magnus

2016-05-11

Proteomics methodology has seen increased application in food authentication, including tandem mass spectrometry of targeted species-specific peptides in raw, processed, or mixed food products. We have previously described an alternative principle that uses untargeted data acquisition and spectral library matching, essentially spectral counting, to compare and identify samples without the need for genomic sequence information in food species populations. Here, we present an interlaboratory comparison demonstrating how a method based on this principle performs in a realistic context. We also increasingly challenge the method by using data from different types of mass spectrometers, by trying to distinguish closely related and commercially important flatfish, and by analyzing heavily contaminated samples. The method was found to be robust in different laboratories, and 94-97% of the analyzed samples were correctly identified, including all processed and contaminated samples.

Quaternary isobaric (vapor + liquid + liquid) equilibrium and (vapor + liquid) equilibrium for the system (water + ethanol + cyclohexane + heptane) at 101.3 kPa

International Nuclear Information System (INIS)

Pequenin, Ana; Asensi, Juan Carlos; Gomis, Vicente

2011-01-01

Highlights: → Water-ethanol-cyclohexane-heptane and water-cyclohexane-heptane isobaric VLLE. → Isobaric experimental data were determined at 101.3 kPa. → A dynamic recirculating still with an ultrasonic homogenizer was used. → The quaternary system does not present quaternary azeotropes. - Abstract: Experimental isobaric (vapor + liquid + liquid) and (vapor + liquid) equilibrium data for the ternary system {water (1) + cyclohexane (2) + heptane (3)} and the quaternary system {water (1) + ethanol (2) + cyclohexane (3) + heptane (4)} were measured at 101.3 kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by Wisniak for testing the thermodynamic consistency of isobaric measurements was used to test the equilibrium data.

Determination of antibiotic residues in southern Baltic Sea sediments using tandem solid-phase extraction and liquid chromatography coupled with tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Grzegorz Siedlewicz

2016-07-01

Full Text Available The main objective of this study was to adapt analytical procedures for determining antibiotic residues in solid and aquatic samples to marine sediments and to investigate the occurrence of 9 sulfonamides, trimethoprim and 2 quinolones in southern Baltic Sea sediments. The analytical procedure was applied to sediment samples characterized as sand and silty sand. The validation results showed that a sensitive and efficient method applying tandem solid-phase extraction (SPE and liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS was obtained. Analytes were determined in the lower ng g−1 range with good accuracy and precision. The proposed analytical procedure was applied to the analysis of 13 sediment samples collected from the Baltic Sea along the Polish coast. Concentrations of antibiotic residues in environmental samples were calculated based on external matrix-matched calibration. Residues of nine out of twelve of the above antibiotics were detected in sediment samples in a concentrations of up to 419.2 ng g−1 d.w. (dry weight. Sulfamethoxazole and sulfachloropyridazine were the most frequently detected compounds (58% of the analyzed samples. The occurrence frequency of trimethoprim was 42% and it was always detected simultaneously with sulfamethoxazole. Preliminary studies on the spatial distribution of the analyzed antibiotics indicate a high level of antibiotics occurring in the Pomeranian Bay and close to the mouths of Polish rivers. The study is the first one to demonstrate the occurrence of antibiotic residues in sediments of the Polish coastal area. The obtained results suggest that sediment can be an important secondary source of antibiotic residues in the marine environment.

New Isotope Analysis Method: Atom Trap Mass Spectrometry

International Nuclear Information System (INIS)

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

2011-01-01

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

Identification of a novel low-level impurity in fungicide pyraclostrobin by high-performance liquid chromatography/tandem mass spectrometry.

Science.gov (United States)

Xia, Kaimin; Shen, ShanShan; Gao, Qun; Shang, Wei; Pan, Yuanjiang; Wu, Jun

2017-05-10

Pyraclostrobin is one kind of new type methoxy acrylate fungicides that has been widely used in agriculture at present, with a lot of advantages including broad spectrum, high efficiency and high selectivity. In this work, a novel low-level impurity in the pyraclostrobin at about 0.2% was separated and characterized by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS). Firstly, the impurity was speculated to possess the same skeleton structure as the main product pyraclostrobin while the methyl group on the methyl ester was substituted to be CH 2 CH 2 Cl on the basis of the on-line multi-stage mass spectrometric behaviors compared with that of pyraclostrobin. Then the accurate molecular weight and element composition of target impurity was verified to be C 20 H 19 Cl 2 N 3 O 4 by high resolution mass spectrometry. Finally, the proposed structure was further confirmed by the 1 H NMR data. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination and pharmacokinetic studies of arecoline in dog plasma by liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Li, Bing; Zhou, Xu-Zheng; Li, Jian-Yong; Yang, Ya-Jun; Niu, Jian-Rong; Wei, Xiao-Juan; Liu, Xi-Wang; Li, Jin-Shan; Zhang, Ji-Yu

2014-10-15

A rapid and sensitive high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of arecoline concentration in dog plasma. Plasma sample was prepared by protein precipitation using n-hexane (containing 1% isoamyl alcohol) with β-pinene as an internal standard. Chromatographic separation was achieved on an Agilent C18 column (4.6×75mm, 3.5μm) using methanol: 5mM ammonium acetate as the mobile phase with isocratic elution. Mass detection was carried out using positive electrospray ionization in multiple reaction monitoring mode. The calibration curve for arecoline was linear over a concentration range of 2-500ng/mL. The intra-day and inter-day accuracy and precision were within the acceptable limits of ±10% at all concentrations. In summary, the LC-MS/MS method described herein was fully validated and successfully applied to the pharmacokinetic study of arecoline hydrobromide tablets in dogs after oral administration. Copyright © 2014. Published by Elsevier B.V.

Determination of fluspirilene in human plasma by liquid chromatography-tandem mass spectrometry with electrospray ionisation.

Science.gov (United States)

Swart, K J; Sutherland, F C; van Essen, G H; Hundt, H K; Hundt, A F

1998-12-18

An ultra-sensitive method for the determination of fluspirilene in plasma was established, using high-performance liquid chromatographic separation with tandem mass spectrometric detection. The samples were extracted with hexane/isoamyl alcohol, separated on a Phenomenex Luna C18 5 mu 150 x 2.1 mm column with a mobile phase consisting of methanol-water-acetic acid (600:400:1) at a flow-rate of 0.3 ml/min. Detection was achieved by a Finnigan Matt mass spectrometer (LCQ) at unit resolution in full scan mode scanning the product ion spectrum from m/z 130-500 and monitoring the transition of the protonated molecular ion at m/z 476.2, to the sum of the largest product ions m/z 371, 342 and 274 (MS-MS). Electrospray ionisation was used for ion production. The mean recovery for fluspirilene was 90% with a lower limit of quantification of 21.50 pg/ml using 1 ml plasma for extraction. This is the first chromatographic method described for the determination of fluspirilene in plasma that is accurate and sensitive enough to be used in pharmacokinetic studies.

Liquid chromatography-tandem mass spectrometry for analysis of intestinal permeability of loperamide in physiological buffer.

Directory of Open Access Journals (Sweden)

Miriam S Rubelt

Full Text Available Analysis of in vitro samples with high salt concentrations represents a major challenge for fast and specific quantification with liquid chromatography-tandem mass spectrometry (LC-MS/MS. To investigate the intestinal permeability of opioids in vitro employing the Ussing chamber technique, we developed and validated a fast, sensitive and selective method based on LC-MS/MS for the determination of loperamide in HEPES-buffered Ringer's solution. Chromatographic separation was achieved with an Atlantis dC18 column, 2.1 mm×20 mm, 3 µm particle size and a gradient consisting of methanol/0.1% formic acid and ammonium acetate. The flow rate was 0.7 ml/min, and the total run time was 3 min. For quantification, two mass transitions for loperamide and a deuterated internal standard (methadone-d(3 were used. The lower limit of loperamide quantification was 0.2 ng/ml. This new LC-MS/MS method can be used for the detection of loperamide in any experimental setup using HEPES-buffered Ringer's solution as a matrix compound.

Quantitation of iothalamate in urine and plasma using liquid chromatography electrospray tandem mass spectrometry (HPLC-ESI-MS/MS).

Science.gov (United States)

Molinaro, Ross J; Ritchie, James C

2010-01-01

The following chapter describes a method to measure iothalamate in plasma and urine samples using high performance liquid chromatography combined with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Methanol and water are spiked with the internal standard (IS) iohexol. Iothalamate is isolated from plasma after IS spiked methanol extraction and from urine by IS spiked water addition and quick-spin filtration. The plasma extractions are dried under a stream of nitrogen. The residue is reconstituted in ammonium acetate-formic acid-water. The reconstituted plasma and filtered urine are injected into the HPLC-ESI-MS/MS. Iothalamate and iohexol show similar retention times in plasma and urine. Quantification of iothalamate in the samples is made by multiple reaction monitoring using the hydrogen adduct mass transitions, from a five-point calibration curve.

Automated mini-column solid-phase extraction cleanup for high-throughput analysis of chemical contaminants in foods by low-pressure gas chromatography – tandem mass spectrometry

Science.gov (United States)

This study demonstrated the application of an automated high-throughput mini-cartridge solid-phase extraction (mini-SPE) cleanup for the rapid low-pressure gas chromatography – tandem mass spectrometry (LPGC-MS/MS) analysis of pesticides and environmental contaminants in QuEChERS extracts of foods. ...

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

Science.gov (United States)

In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence o...

Mass spectrometry-assisted protease substrate screening

DEFF Research Database (Denmark)

Schlüter, Hartmut; Rykl, Jana; Thiemann, Joachim

2007-01-01

-phase chromatography they are analyzed by tandem mass spectrometry and the substrates identified by database searching. The proof of principle in this study is demonstrated by incubating immobilized human plasma proteins with thrombin and by identifying by tandem mass spectrometry the fibrinopeptides, released...

Analysis of hydroxamate siderophores in soil solution using liquid chromatography with mass spectrometry and tandem mass spectrometry with on-line sample preconcentration.

Science.gov (United States)

Olofsson, Madelen A; Bylund, Dan

2015-10-01

A liquid chromatography with electrospray ionization mass spectrometry method was developed to quantitatively and qualitatively analyze 13 hydroxamate siderophores (ferrichrome, ferrirubin, ferrirhodin, ferrichrysin, ferricrocin, ferrioxamine B, D1 , E and G, neocoprogen I and II, coprogen and triacetylfusarinine C). Samples were preconcentrated on-line by a switch-valve setup prior to analyte separation on a Kinetex C18 column. Gradient elution was performed using a mixture of an ammonium formate buffer and acetonitrile. Total analysis time including column conditioning was 20.5 min. Analytes were fragmented by applying collision-induced dissociation, enabling structural identification by tandem mass spectrometry. Limit of detection values for the selected ion monitoring method ranged from 71 pM to 1.5 nM with corresponding values of two to nine times higher for the multiple reaction monitoring method. The liquid chromatography with mass spectrometry method resulted in a robust and sensitive quantification of hydroxamate siderophores as indicated by retention time stability, linearity, sensitivity, precision and recovery. The analytical error of the methods, assessed through random-order, duplicate analysis of soil samples extracted with a mixture of 10 mM phosphate buffer and methanol, appears negligible in relation to between-sample variations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phytochemical analyses of Ziziphus jujuba Mill. var. spinosa seed by ultrahigh performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

Science.gov (United States)

Yang, Bao; Yang, Hongshun; Chen, Feng; Hua, Yanglin; Jiang, Yueming

2013-11-21

Ziziphus jujuba Mill. var. spinosa (Z. jujuba) seeds have attracted much attention within the field of medicine due to their significant effects against disturbances of the central nervous system. Secondary metabolites composition is key to the influence of the pharmaceutical and commercial qualities of this plant. In this work, the phytochemical profile of Z. jujuba seeds was analysed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS). The UPLC-MS/MS information identified the main secondary metabolites in Z. jujuba seeds, including flavonoid C-glycosides, triterpene acids and unsaturated fatty acids. The leading chemical identified by UPLC-MS/MS was betulinic acid, and oleic acid was the leading volatile from the GC-MS results. All the samples tested showed similar phytochemical profiles, but levels of the chemical compounds varied. Principal component analysis revealed the principal secondary metabolites that could define the differences in quality. It was confirmed that the combination of UPLC-MS/MS and GC-MS was an effective technique to demonstrate the pharmaceutical quality of Z. jujuba seeds.

Protonation Sites, Tandem Mass Spectrometry and Computational Calculations of o-Carbonyl Carbazolequinone Derivatives.

Science.gov (United States)

Martínez-Cifuentes, Maximiliano; Clavijo-Allancan, Graciela; Zuñiga-Hormazabal, Pamela; Aranda, Braulio; Barriga, Andrés; Weiss-López, Boris; Araya-Maturana, Ramiro

2016-07-05

A series of a new type of tetracyclic carbazolequinones incorporating a carbonyl group at the ortho position relative to the quinone moiety was synthesized and analyzed by tandem electrospray ionization mass spectrometry (ESI/MS-MS), using Collision-Induced Dissociation (CID) to dissociate the protonated species. Theoretical parameters such as molecular electrostatic potential (MEP), local Fukui functions and local Parr function for electrophilic attack as well as proton affinity (PA) and gas phase basicity (GB), were used to explain the preferred protonation sites. Transition states of some main fragmentation routes were obtained and the energies calculated at density functional theory (DFT) B3LYP level were compared with the obtained by ab initio quadratic configuration interaction with single and double excitation (QCISD). The results are in accordance with the observed distribution of ions. The nature of the substituents in the aromatic ring has a notable impact on the fragmentation routes of the molecules.

Rapid and Precise Measurement of Serum Branched-Chain and Aromatic Amino Acids by Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry

OpenAIRE

Yang, Ruiyue; Dong, Jun; Guo, Hanbang; Li, Hongxia; Wang, Shu; Zhao, Haijian; Zhou, Weiyan; Yu, Songlin; Wang, Mo; Chen, Wenxiang

2013-01-01

BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs) have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standar...

Immunoaffinity chromatography combined with tandem mass spectrometry: A new tool for the selective capture and analysis of brassinosteroid plant hormones

Czech Academy of Sciences Publication Activity Database

Oklešťková, Jana; Tarkowská, Danuše; Eyer, L.; Elbert, Tomáš; Marek, Aleš; Smržová, Z.; Novák, Ondřej; Fránek, M.; Zhabinskii, V.N.; Strnad, Miroslav

2017-01-01

Roč. 170, AUG 1 (2017), s. 432-440 ISSN 0039-9140 R&D Projects: GA MŠk(CZ) LO1204; GA ČR GA14-34792S; GA ČR GJ15-08202Y Institutional support: RVO:61389030 ; RVO:61388963 Keywords : Brassica napus * Brassinosteroids * Enzyme immunoassay * Immunoaffinity chromatography * Liquid chromatography-tandem mass spectrometry * Monoclonal antibodies Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Analytical chemistry; Biochemical research methods (UOCHB-X) Impact factor: 4.162, year: 2016

Rapid and accurate liquid chromatography and tandem mass spectrometry method for the simultaneous quantification of ten metabolic reactions catalyzed by hepatic cytochrome P450 enzymes.

Science.gov (United States)

Shi, Rong; Ma, Bingliang; Wu, Jiasheng; Wang, Tianming; Ma, Yueming

2015-10-01

The hepatic cytochrome P450 enzymes play a central role in the biotransformation of endogenous and exogenous substances. A sensitive high-throughput liquid chromatography with tandem mass spectrometry assay was developed and validated for the simultaneous quantification of the products of ten metabolic reactions catalyzed by hepatic cytochrome P450 enzymes. After the substrates were incubated separately, the samples were pooled and analyzed by liquid chromatography with tandem mass spectrometry using an electrospray ionization source in the positive and negative ion modes. The method exhibited linearity over a broad concentration range, insensitivity to matrix effects, and high accuracy, precision, and stability. The novel method was successfully applied to study the kinetics of phenacetin-O deethylation, coumarin-7 hydroxylation, bupropion hydroxylation, taxol-6 hydroxylation, omeprazole-5 hydroxylation, dextromethorphan-O demethylation, tolbutamide-4 hydroxylation, chlorzoxazone-6 hydroxylation, testosterone-6β hydroxylation, and midazolam-1 hydroxylation in rat liver microsomes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Δ isobars and nuclear saturation

Science.gov (United States)

Ekström, A.; Hagen, G.; Morris, T. D.; Papenbrock, T.; Schwartz, P. D.

2018-02-01

We construct a nuclear interaction in chiral effective field theory with explicit inclusion of the Δ -isobar Δ (1232 ) degree of freedom at all orders up to next-to-next-to-leading order (NNLO). We use pion-nucleon (π N ) low-energy constants (LECs) from a Roy-Steiner analysis of π N scattering data, optimize the LECs in the contact potentials up to NNLO to reproduce low-energy nucleon-nucleon scattering phase shifts, and constrain the three-nucleon interaction at NNLO to reproduce the binding energy and point-proton radius of 4He. For heavier nuclei we use the coupled-cluster method to compute binding energies, radii, and neutron skins. We find that radii and binding energies are much improved for interactions with explicit inclusion of Δ (1232 ) , while Δ -less interactions produce nuclei that are not bound with respect to breakup into α particles. The saturation of nuclear matter is significantly improved, and its symmetry energy is consistent with empirical estimates.

Quantification of Photocyanine in Human Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Application in a Pharmacokinetic Study

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Bing-Tian Bi

2014-01-01

Full Text Available Photocyanine is a novel anticancer drug. Its pharmacokinetic study in cancer patients is therefore very important for choosing doses, and dosing intervals in clinical application. A rapid, selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS method was developed and validated for the determination of photocyanine in patient serum. Sample preparation involved one-step protein precipitation by adding methanol and N,N-dimethyl formamide to 0.1 mL serum. The detection was performed on a triple quadrupole tandem mass spectrometer operating in multiple reaction-monitoring (MRM mode. Each sample was chromatographed within 7 min. Linear calibration curves were obtained for photocyanine at a concentration range of 20–2000 ng/mL (r>0.995, with the lower limit of quantification (LLOQ being 20 ng/mL. The intrabatch accuracy ranged from 101.98% to 107.54%, and the interbatch accuracy varied from 100.52% to 105.62%. Stability tests showed that photocyanine was stable throughout the analytical procedure. This study is the first to utilize the HPLC-MS/MS method for the pharmacokinetic study of photocyanine in six cancer patients who had received a single dose of photocyanine (0.1 mg/kg administered intravenously.

Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

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Ryo eNakabayashi

2015-12-01

Full Text Available In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis. To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs. The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis.

Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

Science.gov (United States)

Nakabayashi, Ryo; Tsugawa, Hiroshi; Kitajima, Mariko; Takayama, Hiromitsu; Saito, Kazuki

2015-01-01

In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS) is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis). To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs). The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine) and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline) identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis. PMID:26734034

DeNovoGUI: an open source graphical user interface for de novo sequencing of tandem mass spectra.

Science.gov (United States)

Muth, Thilo; Weilnböck, Lisa; Rapp, Erdmann; Huber, Christian G; Martens, Lennart; Vaudel, Marc; Barsnes, Harald

2014-02-07

De novo sequencing is a popular technique in proteomics for identifying peptides from tandem mass spectra without having to rely on a protein sequence database. Despite the strong potential of de novo sequencing algorithms, their adoption threshold remains quite high. We here present a user-friendly and lightweight graphical user interface called DeNovoGUI for running parallelized versions of the freely available de novo sequencing software PepNovo+, greatly simplifying the use of de novo sequencing in proteomics. Our platform-independent software is freely available under the permissible Apache2 open source license. Source code, binaries, and additional documentation are available at http://denovogui.googlecode.com .

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

Science.gov (United States)

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

2005-12-01

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

Revisiting hyper- and hypo-androgenism by tandem mass spectrometry.

Science.gov (United States)

Fanelli, Flaminia; Gambineri, Alessandra; Mezzullo, Marco; Vicennati, Valentina; Pelusi, Carla; Pasquali, Renato; Pagotto, Uberto

2013-06-01

Modern endocrinology is living a critical age of transition as far as laboratory testing and biochemical diagnosis are concerned. Novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for steroid measurement in biological fluids have abundantly demonstrated their analytical superiority over immunometric platforms that until now have dominated the world of steroid hormones determination in clinical laboratories. One of the most useful applications of LC-MS/MS is in the hypogonadism and hyperandrogenism field: LC-MS/MS has proved particularly suitable for the detection of low levels of testosterone typical of women and children, and in general more reliable in accurately determining hypogonadal male levels. This technique also offers increased informative power by allowing multi-analytical profiles that give a more comprehensive picture of the overall hormonal asset. Several LC-MS/MS methods for testosterone have been published in the last decade, some of them included other androgen or more comprehensive steroid profiles. LC-MS/MS offers the concrete possibility of achieving a definitive standardization of testosterone measurements and the generation of widely accepted reference intervals, that will set the basis for a consensus on the diagnostic value of biochemical testing. The present review is aimed at summarizing technological advancements in androgen measurements in serum and saliva. We also provide a picture of the state of advancement of standardization of testosterone assays, of the redefinition of androgen reference intervals by novel assays and of studies using LC-MS/MS for the characterization and diagnosis of female hyperandrogenism and male hypogonadism.

Nucleon-deuteron scattering with Δ-isobar excitation: Perturbation theory

International Nuclear Information System (INIS)

Deltuva, A.; Chmielewski, K.; Sauer, P.U.

2003-01-01

A perturbative approach for the description of elastic and inelastic nucleon-deuteron scattering is developed. Its validity is discussed. The aim of the perturbative approach is the isolation of details of different reaction mechanisms. The dynamics is based on a two-baryon potential allowing for the excitation of a nucleon to a Δ isobar. The coupled-channel potential yields an effective three-nucleon force in three-nucleon scattering. The purely nucleonic reference potential is the charge-dependent CD-Bonn potential

Analysis of perchlorate, thiocyanate, nitrate and iodide in human amniotic fluid using ion chromatography and electrospray tandem mass spectrometry

International Nuclear Information System (INIS)

Blount, Benjamin C.; Valentin-Blasini, Liza

2006-01-01

Because of health concerns surrounding in utero exposure to perchlorate, we developed a sensitive and selective method for quantifying iodide, as well as perchlorate and other sodium-iodide symporter (NIS) inhibitors in human amniotic fluid using ion chromatography coupled with electrospray ionization tandem mass spectrometry. Iodide and NIS inhibitors were quantified using a stable isotope-labeled internal standards (Cl 18 O 4 - , S 13 CN - and 15 NO 3 - with excellent assay accuracy of 100%, 98%, 99%, 95% for perchlorate, thiocyanate, nitrate and iodide, respectively, in triplicate analysis of spiked amniotic fluid sample). Excellent analytical precision (<5.2% RSD for all analytes) was found when amniotic fluid quality control pools were repetitively analyzed for iodide and NIS-inhibitors. Selective chromatography and tandem mass spectrometry reduced the need for sample cleanup, resulting in a rugged and rapid method capable of routinely analyzing 75 samples/day. Analytical response was linear across the physiologically relevant concentration range for the analytes. Analysis of a set of 48 amniotic fluid samples identified the range and median levels for perchlorate (0.057-0.71, 0.18 μg/L), thiocyanate (<10-5860, 89 μg/L), nitrate (650-8900, 1620 μg/L) and iodide (1.7-170, 8.1 μg/L). This selective, sensitive, and rapid method will help assess exposure of the developing fetus to low levels of NIS-inhibitors and their potential to inhibit thyroid function

Wipe selection for the analysis of surface materials containing chemical warfare agent nitrogen mustard degradation products by ultra-high pressure liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Willison, Stuart A

2012-12-28

Degradation products arising from nitrogen mustard chemical warfare agent were deposited on common urban surfaces and determined via surface wiping, wipe extraction, and liquid chromatography–tandem mass spectrometry detection. Wipes investigated included cotton gauze, glass fiber filter, non-woven polyester fiber and filter paper, and surfaces included several porous (vinyl tile, painted drywall, wood) and mostly non-porous (laminate, galvanized steel, glass) surfaces. Wipe extracts were analyzed by ultra-high pressure liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) and compared with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) results. An evaluation of both techniques suggests UPLC–MS/MS provides a quick and sensitive analysis of targeted degradation products in addition to being nearly four times faster than a single HPLC run, allowing for greater throughput during a wide-spread release concerning large-scale contamination and subsequent remediation events. Based on the overall performance of all tested wipes, filter paper wipes were selected over other wipes because they did not contain interferences or native species (TEA and DEA) associated with the target analytes, resulting in high percent recoveries and low background levels during sample analysis. Other wipes, including cotton gauze, would require a pre-cleaning step due to the presence of large quantities of native species or interferences of the targeted analytes. Percent recoveries obtained from a laminate surface were 47–99% for all nitrogen mustard degradation products. The resulting detection limits achieved from wipes were 0.2 ng/cm(2) for triethanolamine (TEA), 0.03 ng/cm(2) for N-ethyldiethanolamine (EDEA), 0.1 ng/cm(2) for N-methyldiethanolamine (MDEA), and 0.1 ng/cm(2) for diethanolamine (DEA).

Spinal Anesthesia for Knee Arthroscopy Using Isobaric Bupivacaine and Levobupivacaine: Anesthetic and Neuroophthalmological Assessment

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Monica del-Rio-Vellosillo

2014-01-01

Full Text Available Introduction. The aim of the study was to compare the sensory, motor, and neuroophthalmological effects of isobaric levobupivacaine and bupivacaine when intrathecally administered. Materials and Methods. A prospective, double-blind, randomized study with 60 ASA grade I-II patients aged 18–65 years awaiting knee arthroscopy under spinal anesthesia. Patients received 12.5 mg of isobaric bupivacaine or levobupivacaine. Several features were recorded. Results. No significant intergroup differences were observed for ASA classification, time to micturate, demographic data, surgery duration, and patient/surgeon satisfaction. Similar hemodynamic parameters and sensory/motor blockade duration were found for both groups. There were no neuroophthalmological effects in either group. Sensory (P=0.018 and motor blockade onset (P=0.003 was faster in the bupivacaine group. T6 (T2–T12 and T3 (T2–T12 were the highest sensory block levels for the levobupivacaine and bupivacaine groups, respectively (P=0.008. It took less time to regain maximum motor blockade in the bupivacaine group (P=0.014, and the levobupivacaine group required use of analgesia earlier (P=0.025. Conclusions. Isobaric bupivacaine and levobupivacaine are analogous and well-tolerated anesthetics for knee arthroscopy. However, for bupivacaine, sensory and motor blockade onset was faster, and greater sensory blockade with a longer postoperative painless period was achieved.

Detailed molecular characterization of castor oil ethoxylates by liquid chromatography multistage mass spectrometry.

Science.gov (United States)

Nasioudis, Andreas; van Velde, Jan W; Heeren, Ron M A; van den Brink, Oscar F

2011-10-07

The molecular characterization of castor oil ethoxylates (CASEOs) was studied by reverse-phase liquid chromatography (RPLC) mass spectrometry (MS) and multistage mass spectrometry (MS(n)). The developed RPLC method allowed the separation of the various CASEO components, and especially, the baseline separation of multiple nominal isobars (same nominal mass) and isomers (same exact mass). MS and MS(n) were used for the determination and structure elucidation of various structures and for the discrimination of the isobars and isomers. Different ionization techniques and adduct ions were also tested for optimization of the MS detection and the MS(n) fragmentation. A unique fragmentation pathway of ricinoleic acid is proposed, which can be used as a marker of the polymerization process and the topology of ethoxylation in the CASEO. In addition, characteristic neutral losses of ricinoleic acid reveal its (terminal or internal) position in the molecule. Copyright © 2011 Elsevier B.V. All rights reserved.

Preconcentration and Determination of Perfluoroalkyl Substances (PFASs in Water Samples by Bamboo Charcoal-Based Solid-Phase Extraction Prior to Liquid Chromatography–Tandem Mass Spectrometry

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Ze-Hui Deng

2018-04-01

Full Text Available In this work, bamboo charcoal was used as solid-phase extraction adsorbent for the enrichment of six perfluoroalkyl acids (PFAAs in environmental water samples before liquid chromatography–tandem mass spectrometry analysis. The specific porous structure, high specific surface area, high porosity, and stability of bamboo charcoal were characterized. Several experimental parameters which considerably affect extraction efficiency were investigated and optimized in detail. The experimental data exhibited low limits of detection (LODs (0.01–1.15 ng/L, wide linear range (2–3 orders of magnitude and R ≥ 0.993 within the concentration range of 0.1–1000 ng/L, and good repeatability (2.7–5.0%, n = 5 intraday and 4.8–8.3%, n = 5 interday and reproducibility (5.3–8.0%, n = 3. Bamboo charcoal was successfully used for the enrichment and determination of PFAAs in real environmental water samples. The bamboo charcoal-based solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry analysis possessed great potential in the determination of trace PFAA levels in environmental water samples.

Proteomics of Eosinophil Activation

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Deane F. Mosher

2017-09-01

Full Text Available We recently identified and quantified >7,000 proteins in non-activated human peripheral blood eosinophils using liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS and described phosphoproteomic changes that accompany acute activation of eosinophils by interleukin-5 (IL5 (1. These data comprise a treasure trove of information about eosinophils. We illustrate the power of label-free LC–MS/MS quantification by considering four examples: complexity of eosinophil STATs, contribution of immunoproteasome subunits to eosinophil proteasomes, complement of integrin subunits, and contribution of platelet proteins originating from platelet–eosinophil complexes to the overall proteome. We describe how isobaric labeling enables robust sample-to-sample comparisons and relate the 220 phosphosites that changed significantly upon treatment with IL5 to previous studies of eosinophil activation. Finally, we review previous attempts to leverage the power of mass spectrometry to discern differences between eosinophils of healthy subjects and those with eosinophil-associated conditions and point out features of label-free quantification and isobaric labeling that are important in planning future mass spectrometric studies.

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...

MZDASoft: a software architecture that enables large-scale comparison of protein expression levels over multiple samples based on liquid chromatography/tandem mass spectrometry.

Science.gov (United States)

Ghanat Bari, Mehrab; Ramirez, Nelson; Wang, Zhiwei; Zhang, Jianqiu Michelle

2015-10-15

Without accurate peak linking/alignment, only the expression levels of a small percentage of proteins can be compared across multiple samples in Liquid Chromatography/Mass Spectrometry/Tandem Mass Spectrometry (LC/MS/MS) due to the selective nature of tandem MS peptide identification. This greatly hampers biomedical research that aims at finding biomarkers for disease diagnosis, treatment, and the understanding of disease mechanisms. A recent algorithm, PeakLink, has allowed the accurate linking of LC/MS peaks without tandem MS identifications to their corresponding ones with identifications across multiple samples collected from different instruments, tissues and labs, which greatly enhanced the ability of comparing proteins. However, PeakLink cannot be implemented practically for large numbers of samples based on existing software architectures, because it requires access to peak elution profiles from multiple LC/MS/MS samples simultaneously. We propose a new architecture based on parallel processing, which extracts LC/MS peak features, and saves them in database files to enable the implementation of PeakLink for multiple samples. The software has been deployed in High-Performance Computing (HPC) environments. The core part of the software, MZDASoft Parallel Peak Extractor (PPE), can be downloaded with a user and developer's guide, and it can be run on HPC centers directly. The quantification applications, MZDASoft TandemQuant and MZDASoft PeakLink, are written in Matlab, which are compiled with a Matlab runtime compiler. A sample script that incorporates all necessary processing steps of MZDASoft for LC/MS/MS quantification in a parallel processing environment is available. The project webpage is http://compgenomics.utsa.edu/zgroup/MZDASoft. The proposed architecture enables the implementation of PeakLink for multiple samples. Significantly more (100%-500%) proteins can be compared over multiple samples with better quantification accuracy in test cases. MZDASoft

Determination of hydroxylated polycyclic aromatic hydrocarbons by HPLC-photoionization tandem mass spectrometry in wood smoke particles and soil samples.

Science.gov (United States)

Avagyan, Rozanna; Nyström, Robin; Boman, Christoffer; Westerholm, Roger

2015-06-01

A simple and fast method for analysis of hydroxylated polycyclic aromatic hydrocarbons using pressurized liquid extraction and high performance liquid chromatography utilizing photoionization tandem mass spectrometry was developed. Simultaneous separation and determination of nine hydroxylated polycyclic aromatic hydrocarbons and two hydroxy biphenyls could be performed in negative mode with a run time of 12 min, including equilibration in 5 min. The calibration curves were in two concentration ranges; 1-50 ng/mL and 0.01-50 μg/mL, with coefficients of correlation R (2) > 0.997. The limits of detection and method quantification limits were in the range of 9-56 pg and 5-38 ng/g, respectively. A two-level full factorial experimental design was used for screening of conditions with the highest impact on the extraction. The extraction procedure was automated and suitable for a large number of samples. The extraction recoveries ranged from 70 to 102 % and the matrix effects were between 92 and 104 %. The overall method was demonstrated on wood smoke particles and soil samples with good analytical performance, and five OH-PAHs were determined in the concentration range of 0.19-210 μg/g. As far as we know, hydroxylated polycyclic aromatic hydrocarbons were determined in wood smoke and soil samples using photoionization mass spectrometry for the first time in this present study. Accordingly, this study shows that high performance liquid chromatography photoionization tandem mass spectrometry can be a good option for the determination of hydroxylated polycyclic aromatic hydrocarbons in complex environmental samples. Graphical Abstract The method developed in this study was used to determine hydroxylated polycyclic aromatic hydrocarbons in wood smoke and soil.

Liquid chromatography with tandem mass spectrometry quantification of urinary proanthocyanin A2 dimer and its potential use as a biomarker of cranberry intake.

Science.gov (United States)

Walsh, Jason M; Ren, Xiaobai; Zampariello, Carly; Polasky, Daniel A; McKay, Diane L; Blumberg, Jeffrey B; Chen, C-Y Oliver

2016-01-01

The lack of a biomarker for the consumption of cranberries has confounded the interpretation of several studies investigating the effect of cranberry products, especially juices, on health outcomes. The objectives of this pilot study were to develop a liquid chromatography tandem mass spectrometric method for the quantification of the proanthocyanin dimer A-2 in human urine and validate urinary proanthocyanin dimer A-2 as a biomarker of cranberry intake. Five healthy, nonsmoking, premenopausal women (20-30 years of age, body mass index: 18.5-25 kg/m(2) ) were assigned to consume a cranberry beverage containing 140 mg proanthocyanin and 35 kilocalories at 237 mL/day, according to a weekly dosing schedule for 7 weeks. Eleven 24 h and morning spot urine samples each were collected from each subject. A reliable, sensitive method for the detection of proanthocyanin dimer A-2 in urine using liquid chromatography with tandem mass spectrometry was developed with a limit of quantitation of 0.25 ng/mL and a relative standard deviation of 7.26%, precision of 5.7%, and accuracy of 91.7%. While proanthocyanin dimer A-2 was quantifiable in urine, it did not appear to be excreted in a concentration that corresponded to the dosing schedule and intake of cranberry juice. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-sensitivity simultaneous liquid chromatography-tandem mass spectrometry assay of ethinyl estradiol and levonorgestrel in human plasma

Institute of Scientific and Technical Information of China (English)

Abhishek Gandhi; Swati Guttikar; Priti Trivedi

2015-01-01

A sensitive and simultaneous liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of ethinyl estradiol and levonorgestrel. The analytes were extracted with methyl-tert-butyl ether: n-hexane (50:50, v/v) solvent mixture, followed by dansyl derivatization. The chromatographic separation was performed on a Kinetex C18 (50 mm × 4.6 mm, 2.6μm) column with a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile in gradient composition. The mass transitions were monitored in electrospray positive ionization mode. The assay exhibited a linear range of 0.100-20.0 ng/mL for levonorgestrel and 4.00-500 pg/mL for ethinyl estradiol in human plasma. A run time of 9.0 min for each sample made it possible to analyze a throughput of more than 100 samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic and bioequivalence studies.

Simultaneous detection of low and high molecular weight carbonylated compounds derived from lipid peroxidation by electrospray ionization-tandem mass spectrometry.

Science.gov (United States)

Milic, Ivana; Hoffmann, Ralf; Fedorova, Maria

2013-01-02

Reactive oxygen species (ROS) and other oxidative agents such as free radicals can oxidize polyunsaturated fatty acids (PUFA) as well as PUFA in lipids. The oxidation products can undergo consecutive reactions including oxidative cleavages to yield a chemically diverse group of products, such as lipid peroxidation products (LPP). Among them are aldehydes and ketones ("reactive carbonyls") that are strong electrophiles and thus can readily react with nucleophilic side chains of proteins, which can alter the protein structure, function, cellular distribution, and antigenicity. Here, we report a novel technique to specifically derivatize both low molecular and high molecular weight carbonylated LPP with 7-(diethylamino)coumarin-3-carbohydrazide (CHH) and analyze all compounds by electrospray ionization-mass spectrometry (ESI-MS) in positive ion mode. CHH-derivatized compounds were identified by specific neutral losses or fragment ions. The fragment ion spectra displayed additional signals that allowed unambiguous identification of the lipid, fatty acids, cleavage sites, and oxidative modifications. Oxidation of docosahexaenoic (DHA, 22:6), arachidonic (AA, 20:4), linoleic (LA, 18:2), and oleic acids (OA, 18:1) yielded 69 aliphatic carbonyls, whose structures were all deduced from the tandem mass spectra. When four phosphatidylcholine (PC) vesicles containing the aforementioned unsaturated fatty acids were oxidized, we were able to deduce the structures of 122 carbonylated compounds from the tandem mass spectra of a single shotgun analysis acquired within 15 min. The high sensitivity (LOD ∼ 1 nmol/L for 4-hydroxy-2-nonenal, HNE) and a linear range of more than 3 orders of magnitude (10 nmol/L to 10 μmol/L for HNE) will allow further studies on complex biological samples including plasma.

Simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma using liquid chromatography tandem mass spectrometry.

Science.gov (United States)

Gupta, V K; Jain, Rajeev; Lukram, Ojitkumar; Agarwal, Shilpi; Dwivedi, Ashish

2011-01-15

A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma. The solid-phase extraction technique was used for the extraction of ramipril, ramiprilat and telmisartan from human plasma. Trandolaprilat and hydrochlorothiazide were used as the internal standards (ISs). Chromatography was performed on a Hypurity C18, 5 μm, 50 mm × 4.6mm column, with the mobile phase consisting of ammonium acetate and acetonitrile (in a 20:80 ratio), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub-nanogram levels. The method was validated and the lower limit of quantification for ramipril, ramiprilat and telmisartan was found to be 0.1 ng mL(-1), 0.1 ng mL(-1) and 2 ng mL(-1), respectively. The mean recovery for ramipril, ramiprilat and telmisartan ranged from 90.1 to 104.1%. This method increased the sensitivity and selectivity; resulting in high-throughput analysis of ramipril, ramiprilat and telmisartan using two different ISs in a single experiment for bioequivalence studies, with a chromatographic run time of 1.5 min only. Copyright © 2010 Elsevier B.V. All rights reserved.

Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

Science.gov (United States)

A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

Detection of lysergic acid diethylamide (LSD) in urine by gas chromatography-ion trap tandem mass spectrometry.

Science.gov (United States)

Sklerov, J H; Kalasinsky, K S; Ehorn, C A

1999-10-01

A confirmatory method for the detection and quantitation of lysergic acid diethylamide (LSD) is presented. The method employs gas chromatography-tandem mass spectrometry (GC-MS-MS) using an internal ionization ion trap detector for sensitive MS-MS-in-time measurements of LSD extracted from urine. Following a single-step solid-phase extraction of 5 mL of urine, underivatized LSD can be measured with limits of quantitation and detection of 80 and 20 pg/mL, respectively. Temperature-programmed on-column injections of urine extracts were linear over the concentration range 20-2000 pg/mL (r2 = 0.999). Intraday and interday coefficients of variation were LSD-positive samples in this laboratory. Comparisons with alternate GC-MS methods and extraction procedures are discussed.

Determination of cholesterol and four phytosterols in foods without derivatization by gas chromatography-tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Yan-Zong Chen

2015-12-01

Full Text Available In this study, a method for determination of cholesterol and four phytosterols by gas chromatography coupled with electron impact ionization mode–tandem mass spectrometry without derivatization in general food was developed. The sample was saponified with 7.5% KOH in methanol. After heating on hot plate and reflux for 60 minutes, the saponified portion was extracted with n-hexane/petroleum ether (50:50, v/v. The extracts were evaporated with rotary evaporator and then redissolved with tetrahydrofuran. The tetrahydrofuran layer was transferred into an injection vial and analyzed by gas chromatography on a 30 m VF-5 column. Limit of quantification was 2 mg/kg. Recoveries of cholesterol and four phytosterols from general food were between 91% and 100%.

Liquid chromatography tandem mass spectrometry determination of total budesonide levels in dog plasma after inhalation exposure.

Science.gov (United States)

Berg, Seija; Melamies, Marika; Rajamäki, Minna; Vainio, Outi; Peltonen, Kimmo

2012-01-01

A sensitive and selective method to quantify budesonide in dog plasma samples was developed and fully validated. Liquid-liquid extraction was followed by solid-phase extraction and liquid chromatography-tandem mass spectrometry with electrospray ionization. After reconstitution of the analytes in the mobile phase, samples were analysed by reversed-phase liquid chromatography with isocratic elution. d8-Budesonide was used as an internal standard, and characteristic transitions of d8-budesonide and budesonide were used for quantification. The method was validated with respect to selectivity, specificity, linearity, recovery, repeatability, reproducibility and limits of detection and quantification. The validated method was successfully applied to monitor the plasma levels of budesonide in dogs exposed to clinical doses of inhaled and intravenous drug.

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.

Optimization of collision/reaction gases for determination of 90Sr in atmospheric particulate matter by inductively coupled plasma tandem mass spectrometry after direct introduction of air via a gas-exchange device

Science.gov (United States)

Suzuki, Yoshinari; Ohara, Ryota; Matsunaga, Kirara

2017-09-01

Nuclear power plant accidents release radioactive strontium 90 (90Sr) into the environment. Monitoring of 90Sr, although important, is difficult and time consuming because it emits only beta radiation. We have developed a new analytical system that enables real-time analysis of 90Sr in atmospheric particulate matter with an analytical run time of only 10 min. Briefly, after passage of an air sample through an impactor, a small fraction of the sample is introduced into a gas-exchange device, where the air is replaced by Ar. Then the sample is directly introduced into an inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) system equipped with a collision/reaction cell to eliminate isobaric interferences on 90Sr from 90Zr+, 89Y1H+, and 90Y+. Experiments with various reaction gas conditions revealed that these interferences could be minimized under the following optimized conditions: 1.0 mL min- 1 O2, 10.0 mL min- 1 H2, and 1.0 mL min- 1 NH3. The estimated background equivalent concentration and estimated detection limit of the system were 9.7 × 10- 4 and 3.6 × 10- 4 ng m- 3, respectively, which are equivalent to 4.9 × 10- 6 and 1.8 × 10- 6 Bq cm- 3. Recoveries of Sr in PM2.5 measured by real-time analysis compared to those obtained by simultaneously collection on filter was 53 ± 23%, and using this recovery, the detection limit as PM2.5 was estimated to be 3.4 ± 1.5 × 10- 6 Bq cm- 3. That is, this system enabled detection of 90Sr at concentrations < 5 × 10- 6 Bq cm- 3 even considering the insufficient fusion/vaporization/ionization efficiency of Sr in PM2.5.

Detection, characterization and quantification of salicylic acid conjugates in plant extracts by ESI tandem mass spectrometric techniques.

Science.gov (United States)

Pastor, Victoria; Vicent, Cristian; Cerezo, Miguel; Mauch-Mani, Brigitte; Dean, John; Flors, Victor

2012-04-01

An approach for the detection and characterization of SA derivatives in plant samples is presented based on liquid chromatography coupled to electrospray ionization (ESI) tandem mass spectrometric techniques. Precursor ion scan methods using an ESI triple quadrupole spectrometer for samples from plants challenged with the virulent Pseudomonas syringae pv tomato DC3000 allowed us to detect two potential SA derivatives. The criterion used to consider a potential SA derivative is based on the detection of analytes in the precursor ion scan chromatogram upon selecting m/z 137 and m/z 93 that correspond to the salicylate and its main product ion, respectively. Product ion spectra of the newly-detected analytes as well as accurate m/z determinations using an ESI Q-time-of-flight instrument were registered as means of characterization and strongly suggest that glucosylated forms of SA at the carboxylic and at the phenol functional groups are present in plant samples. The specific synthesis and subsequent chromatography of salicylic glucosyl ester (SGE) and glucosyl salicylate (SAG) standards confirmed the chemical identity of both peaks that were obtained applying different tandem mass spectrometric techniques and accurate m/z determinations. A multiple reaction monitoring method has been developed and applied to plant samples. The advantages of this LC-ESI-MS/MS methods with respect to the traditional analysis of glucosyl conjugates are also discussed. Preliminary results revealed that SA and the glucosyl conjugates are accumulated in Arabidopsis thaliana in a time dependent manner, accordingly to the up-regulation of SA-dependent defenses following P. syringae infection. This technique applied to plant hormones or fragment ions may be useful to obtain chemical family members of plant metabolites and help identify their contribution in the signaling of plant defenses. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Tandem Affinity Purification Approach Coupled to Mass Spectrometry to Identify Post-translational Modifications of Histones Associated with Chromatin-Binding Proteins.

Science.gov (United States)

Beyer, Sophie; Robin, Philippe; Ait-Si-Ali, Slimane

2017-01-01

Protein purification by tandem affinity purification (TAP)-tag coupled to mass spectrometry analysis is usually used to reveal protein complex composition. Here we describe a TAP-tag purification of chromatin-bound proteins along with associated nucleosomes, which allow exhaustive identification of protein partners. Moreover, this method allows exhaustive identification of the post-translational modifications (PTMs) of the associated histones. Thus, in addition to partner characterization, this approach reveals the associated epigenetic landscape that can shed light on the function and properties of the studied chromatin-bound protein.

Determination of levofloxacin in human serum using liquid chromatography tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Samiksha Ghimire

2018-01-01

Full Text Available A rapid liquid chromatography tandem-mass spectrometry method was developed for the determination of levofloxacin and its metabolite (desmethyl-levofloxacin in human serum. Sample preparation was done using protein precipitation technique. Our method had a run time of 2.5 min and retention times of 1.6 min for all analytes. The standard curves were linear within the concentration range of 0.10 to 5.00 mg/L for levofloxacin and 0.10 to 4.99 mg/L for desmethyl- levofloxacin; a correlation coefficient (R2 of 0.999 and 0.998 respectively. The lower limit of quantification for both analytes was 0.10 mg/L. Within-day precision ranged from 1.4% and 2.4% for levofloxacin, 1.5% to 5% for desmethyl-levofloxacin and between-day precision ranged from 3.6% to 4.1% for levofloxacin and 0.0% to 3.3% for desmethyl-levofloxacin; whereas, accuracy ranged from 0.1% to 12.7% for levofloxacin and 0.2% to 15.6% for desmethyl-levofloxacin. This method could be a useful asset for routine therapeutic drug monitoring of levofloxacin in multi-drug resistant tuberculosis patients.

Characterization of aromatic organosulfur model compounds relevant to fossil fuels by using atmospheric pressure chemical ionization with CS2 and high-resolution tandem mass spectrometry.

Science.gov (United States)

Tang, Weijuan; Sheng, Huaming; Jin, Chunfen; Riedeman, James S; Kenttämaa, Hilkka I

2016-04-15

The chemistry of desulfurization involved in processing crude oil is greatly dependent on the forms of sulfur in the oil. Sulfur exists in different chemical bonding environments in fossil fuels, including those in thiophenes and benzothiophenes, thiols, sulfides, and disulfides. In this study, the fragmentation behavior of the molecular ions of 17 aromatic organosulfur compounds with various functionalities was systematically investigated by using high-resolution tandem mass spectrometry. Multiple-stage tandem mass spectrometric experiments were carried out using a linear quadrupole ion trap (LQIT) equipped with an atmospheric pressure chemical ionization (APCI) source. (+)APCI/CS2 was used to generate stable dominant molecular ions for all the compounds studied except for three sulfides that also showed abundant fragment ions. The LQIT coupled with an orbitrap mass spectrometer was used for elemental composition analysis, which facilitated the identification of the neutral molecules lost during fragmentation. The characteristic fragment ions generated in MS(2) and MS(3) experiments provide clues for the chemical bonding environment of sulfur atoms in the examined compounds. Upon collision-induced dissociation (CID), the molecular ions can lose the sulfur atom in a variety of ways, including as S (32 Da), HS(•) (33 Da), H2 S (34 Da), CS (44 Da), (•) CHS (45 Da) and CH2 S (46 Da). These neutral fragments are not only indicative of the presence of sulfur, but also of the type of sulfur present in the compound. Generally, losses of HS(•) and H2 S were found to be associated with compounds containing saturated sulfur functionalities, while losses of S, CS and (•) CHS were more common for heteroaromatic sulfur compounds. High-resolution tandem mass spectrometry with APCI/CS2 ionization is a viable approach to determining the types of organosulfur compounds. It can potentially be applied to analysis of complex mixtures, which is beneficial to improving the

[Clinical research of hyperbaric, isobaric, and hypobaric solutions of bupivacaine in continuous spinal anesthesia].

Science.gov (United States)

Yang, Hong-wei; Bai, Nian-yue; Guo, Qu-lian

2005-02-01

To compare the anesthesia properities of hyperbaric bupivacaine with those of isobaric and hypobaric solutions when administered in the supine position undergoing hip surgery or lower limb surgery using continuous spinal anesthesia. Sixty patients( ASA I approximately III ) scheduled for hip or lower limb surgery were randomly divided into 3 groups with 20 patients in each group: Group A: 0. 375% hyperbaric bupivacaine solutions; Group B :0.375% isobaric bupivacaine solutions; and Group C: 0. 375% hypobaric bupivacaine solutions. The following variables were measured every 2 minutes during the first 30 minutes after the intrathecal injection : the onset time of sensation block, the highest plane of analgesia, the time to reach complete motor blockade, and the plane of analgesia and the extent of lower extremities' movement (modified bromage score, BMS) at different time after the administration. Meanwhile the changes of hemodynamics were recorded. There was no statistical difference among the basic conditions ( P > 0.05). The onset time of sensation block, and the time to reach complete motor blockade, and the time receiving the highest sharp pain sensory block in Group A were significantly shorter than those in Group B and Group C ( P hyperbaric group was significantly higher than in both the isobaric and the hypobaric groups ( P hyperbaric group decreased significantly after the intrathecal injection( P hyperbaric bupivacaine produces major hemodynamic consequences with high cephalad spread and 0. 375% hypobaric bupivacaine has a too long onset time.

Detection of Radiation-Exposure Biomarkers by Differential Mobility Prefiltered Mass Spectrometry (DMS-MS).

Science.gov (United States)

Coy, Stephen L; Krylov, Evgeny V; Schneider, Bradley B; Covey, Thomas R; Brenner, David J; Tyburski, John B; Patterson, Andrew D; Krausz, Kris W; Fornace, Albert J; Nazarov, Erkinjon G

2010-04-15

Technology to enable rapid screening for radiation exposure has been identified as an important need, and, as a part of a NIH / NIAD effort in this direction, metabolomic biomarkers for radiation exposure have been identified in a recent series of papers. To reduce the time necessary to detect and measure these biomarkers, differential mobility spectrometry - mass spectrometry (DMS-MS) systems have been developed and tested. Differential mobility ion filters preselect specific ions and also suppress chemical noise created in typical atmospheric-pressure ionization sources (ESI, MALDI, and others). Differential-mobility-based ion selection is based on the field dependence of ion mobility, which, in turn, depends on ion characteristics that include conformation, charge distribution, molecular polarizability, and other properties, and on the transport gas composition which can be modified to enhance resolution. DMS-MS is able to resolve small-molecule biomarkers from nearly-isobaric interferences, and suppresses chemical noise generated in the ion source and in the mass spectrometer, improving selectivity and quantitative accuracy. Our planar DMS design is rapid, operating in a few milliseconds, and analyzes ions before fragmentation. Depending on MS inlet conditions, DMS-selected ions can be dissociated in the MS inlet expansion, before mass analysis, providing a capability similar to MS/MS with simpler instrumentation. This report presents selected DMS-MS experimental results, including resolution of complex test mixtures of isobaric compounds, separation of charge states, separation of isobaric biomarkers (citrate and isocitrate), and separation of nearly-isobaric biomarker anions in direct analysis of a bio-fluid sample from the radiation-treated group of a mouse-model study. These uses of DMS combined with moderate resolution MS instrumentation indicate the feasibility of field-deployable instrumentation for biomarker evaluation.

Liquid chromatography-tandem mass spectrometry method for determination of panel of neurotransmitters in cerebrospinal fluid from the rat model for tauopathy.

Science.gov (United States)

Kovac, Andrej; Somikova, Zuzana; Zilka, Norbert; Novak, Michal

2014-02-01

Alzheimer's disease (AD) is still being recognized today as an unmet medical need. Currently, there is no cure and early preclinical diagnostic assay available for AD. Therefore much attention is now being directed at the development of novel methods for quantitative determination of AD biomarkers in the cerebrospinal fluid (CSF). Here, we describe the liquid chromatography-tandem mass spectrometry method for determination of 5-hydroxytryptamine (SER), 5-hydroxyindoleacetic acid (5-HIAA), homovanilic acid (HVA), noradrenaline (NADR), adrenaline (ADR), dopamine (DA), glutamic acid (Glu), γ-aminobutyric acid (GABA), 3,4-dihydroxyphenylacetic acid (DOPAC) and histamine (HIS) in cerebrospinal fluid (CSF) from the rat model for human tauopathy. The benzoyl chloride was used as pre-column derivatization reagents. Neurotransmitters and metabolites were analysed on ultra performance liquid chromatography (UPLC) on C18 column in combination with tandem mass spectrometry. The method is simple, highly sensitive and showed excellent linearity with regression coefficients higher than 0.99. The accuracy was in a range of 93-113% for all analytes. The inter-day precision (n=5 days), expressed as %RSD, was in a range 2-10% for all analytes. Using this method we detected significant changes of CSF levels of two important neurotransmitters/metabolites, ADR and 5-HIAA, which correlates with progression of neurodegeneration in our animal model. © 2013 Published by Elsevier B.V.

Quantitative determination of hederagenin in rat plasma and cerebrospinal fluid by ultra fast liquid chromatography-tandem mass spectrometry method.

Science.gov (United States)

Yang, Xuemei; Li, Guoliang; Chen, Lingyun; Zhang, Cong; Wan, Xinxiang; Xu, Jiangping

2011-07-01

A rapid, sensitive and selective method was developed for the quantitative determination of hederagenin in rat plasma and cerebrospinal fluid (CSF) by ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS). It has been successfully applied in a pharmacokinetic study of hederagenin in the central nervous system (CNS). Sample pretreatment involved a simple protein precipitation with methanol and a one-step extraction with ethyl acetate. Separation was carried out in a Shim-pack XR-ODS II (75 mm × 2.0 mm, i.d., 2.1 μm) column with gradient elution at a flow rate of 0.35 mL/min. The mobile phase was 5mM ammonium acetate and acetonitrile. Detection was performed in a triple-quadruple tandem mass spectrometer by multiple-reaction-monitoring mode via electrospray ionization. A linear calibration curve for hederagenin was obtained over a concentration range of 0.406 (lower limit of quantification, LLOQ) to 203 ng/mL (r² > 0.99) for both plasma and CSF. The intra-day and inter-day precision (relative standard deviation, RSD) values were less than 15%. At all quality control (QC) levels, the accuracy (relative error, RE) was within -9.0% and 11.1% for plasma and CSF, respectively. The pharmacokinetics results indicated that hederagenin could pass through the blood-brain barrier. This UFLC-MS/MS method demonstrates higher sensitivity and sample throughput than previous methods. It was also successfully applied to the pharmacokinetic study of hederagenin following oral administration of Fructus akebiae extract in rats. Copyright © 2011 Elsevier B.V. All rights reserved.

Residue analysis of orthosulfamuron herbicide in fatty rice using liquid chromatography–tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Young-Jun Lee

2015-05-01

Full Text Available In the present study, orthosulfamuron residues were extracted from fatty (unpolished rice and rice straw using a modified QuEChERS method and analyzed using liquid chromatography–tandem mass spectrometry. The matrix-matched calibration was linear over the concentration ranges of 0.01–2.0 mg/kg with determination coefficient (R2 ⩾ 0.997. The recovery rates at two fortification levels (0.1 and 0.5 mg/kg were satisfactory and ranged between 88.1% and 100.6%, with relative standard deviation (RSD <8%. The limit of quantitation, 0.03 mg/kg, was lower than the maximum residue limit, 0.05 mg/kg, set by the Ministry of Food and Drug Safety in the Republic of Korea. The developed method was applied successfully to field samples harvested at 116 days and none of the samples were positive for the residue.

Quantitation of 5-Methyltetrahydrofolate in Cerebrospinal Fluid Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.

Science.gov (United States)

Arning, Erland; Bottiglieri, Teodoro

2016-01-01

We describe a simple stable isotope dilution method for accurate and precise measurement of cerebrospinal fluid (CSF) 5-methyltetrahydrofolate (5-MTHF) as a clinical diagnostic test. 5-MTHF is the main biologically active form of folic acid and is involved in regulation of homocysteine and DNA synthesis. Measurement of 5-MTHF in CSF provides diagnostic information regarding diseases affecting folate metabolism within the central nervous system, in particular inborn errors of folate metabolism. Determination of 5-MTHF in CSF (50 μL) was performed utilizing high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). 5-MTHF in CSF is determined by a 1:2 dilution with internal standard (5-MTHF-(13)C5) and injected directly onto the HPLC-ESI-MS/MS system. Each assay is quantified using a five-point standard curve (25-400 nM) and has an analytical measurement range of 3-1000 nM.

A novel strategy for the determination of polycyclic aromatic hydrocarbon monohydroxylated metabolites in urine using ultra-high-performance liquid chromatography with tandem mass spectrometry.

Czech Academy of Sciences Publication Activity Database

Lanková, D.; Urbancová, K.; Šrám, Radim; Hajslová, J.; Pulkrabová, J.

2016-01-01

Roč. 408, č. 10 (2016), s. 2515-2525 ISSN 1618-2642 R&D Projects: GA ČR(CZ) GA13-13458S Institutional support: RVO:68378041 Keywords : monohydroxylated metabolites of polycyclic aromatic hydrocarbons * SRM 3673 * tandem mass spectrometry * ultra-high-performance liquid chromatography * urine Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.431, year: 2016

Liquid extraction surface analysis (LESA) of food surfaces employing chip-based nano-electrospray mass spectrometry.

Science.gov (United States)

Eikel, Daniel; Henion, Jack

2011-08-30

An automated surface-sampling technique called liquid extraction surface analysis (LESA), coupled with infusion nano-electrospray high-resolution mass spectrometry and tandem mass spectrometry (MS/MS), is described and applied to the qualitative determination of surface chemical residues resulting from the artificial spraying of selected fresh fruits and vegetables with representative pesticides. Each of the targeted pesticides was readily detected with both high-resolution and full-scan collision-induced dissociation (CID) mass spectra. In the case of simazine and sevin, a mass resolution of 100,000 was insufficient to distinguish the isobaric protonated molecules for these compounds. When the surface of a spinach leaf was analyzed by LESA, trace levels of diazinon were readily detected on the spinach purchased directly from a supermarket before they were sprayed with the five-pesticide mixture. A 30 s rinse under hot running tap water appeared to quantitatively remove all remaining residues of this pesticide. Diazinon was readily detected by LESA analysis on the skin of the artificially sprayed spinach. Finally, incurred pyrimethanil at a level of 169 ppb in a batch slurry of homogenized apples was analyzed by LESA and this pesticide was readily detected by both high-resolution mass spectrometry and full-scan CID mass spectrometry, thus showing that pesticides may also be detected in whole fruit homogenized samples. This report shows that representative pesticides on fruit and vegetable surfaces present at levels 20-fold below generally allowed EPA tolerance levels are readily detected and confirmed by the title technologies making LESA-MS as interesting screening method for food safety purposes. Copyright © 2011 John Wiley & Sons, Ltd.

Mass spectrometric detection of radiocarbon for dating applications

OpenAIRE

Synal Hans-Arno

2013-01-01

Radiocarbon is still the most important nuclide measured by accelerator mass spectrometry (AMS). The related capabilities for dating and tracer studies are eminent not only in archaeology but also drive important applications in the earth and environmental sciences as well as in biomedical research. So far standard mass spectrometric systems have not been capable of radiocarbon dating because of interfering molecular isobars which however can be completely eliminated in charge changing proces...

Reinforcement of spinal anesthesia by epidural injection of saline: a comparison of hyperbaric and isobaric tetracaine.

Science.gov (United States)

Yamazaki, Y; Mimura, M; Hazama, K; Namiki, A

2000-04-25

An epidural injection of saline was reported to extend spinal anesthesia because of a volume effect. The aim of this study was to evaluate the influence of the baricity of spinal local anesthetics upon the extension of spinal anesthesia by epidural injection of saline. Forty patients undergoing elective lower-limb surgery were randomly allocated to four groups of 10 patients each. Group A received no epidural injection after the spinal administration of hyperbaric tetracaine (dissolved in 10% glucose). Group B received an epidural injection of 8 ml of physiological saline 20 min after spinal hyperbaric tetracaine. Group C received no epidural injection after spinal isobaric tetracaine (dissolved in physiological saline). Group D received an epidural injection of 8 ml of saline 20 min after spinal isobaric tetracaine. The level of analgesia was examined by the pinprick method at 5-min intervals. The levels of analgesia 20 min after spinal anesthesia were significantly higher in hyperbaric groups than in isobaric groups [T5 (T2-L2) vs. T7 (T3-12)]. After epidural injection of saline, the levels of analgesia in groups B and D were significantly higher than in groups A and C. The segmental increases after epidural saline injection were 2 (0-3) in group B and 2 (1-7) in group D. Sensation in the sacral area remained 20 min after spinal block in one patient in group D; however, it disappeared after epidural saline injection. In this study, 8 ml of epidural saline extended spinal analgesia. However, there was no difference between the augmenting effect in isobaric and hyperbaric spinal anesthesia. We conclude that the reinforcement of spinal anesthesia by epidural injection of saline is not affected by the baricity of the spinal anesthetic solution used.

Tandem mass spectrometry: a convenient approach in the dosage of steviol glycosides in Stevia sweetened commercial food beverages.

Science.gov (United States)

Di Donna, L; Mazzotti, F; Santoro, I; Sindona, G

2017-05-01

The use of sweeteners extracted from leaves of the plant species Stevia rebaudiana is increasing worldwide. They are recognized as generally recognized as safe by the US-FDA and approved by EU-European Food Safety Authority, with some recommendation on the daily dosage that should not interfere with glucose metabolism. The results presented here introduce an easy analytical approach for the identification and assay of Stevia sweeteners in commercially available soft drink, based on liquid chromatography coupled to tandem mass spectrometry, using a natural statin-like molecule, Brutieridin, as internal standard. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Baryonic 3P2 superfluidity under charged-pion condensation with Δ isobar

International Nuclear Information System (INIS)

Takatsuka, T.; Tamagaki, R.

1999-01-01

We study the baryonic 3 P 2 superfluidity under charged-pion condensation with isobar (Δ) degrees of freedom. After a remark on motivations of the present study, the outline of theoretical framework is briefly described, typical results of the superfluid critical temperature are shown, and the possibility of coexistence of the superfluid with charged-pion condensation is discussed. (author)

False-Positive Rate Determination of Protein Target Discovery using a Covalent Modification- and Mass Spectrometry-Based Proteomics Platform

Science.gov (United States)

Strickland, Erin C.; Geer, M. Ariel; Hong, Jiyong; Fitzgerald, Michael C.

2014-01-01

Detection and quantitation of protein-ligand binding interactions is important in many areas of biological research. Stability of proteins from rates of oxidation (SPROX) is an energetics-based technique for identifying the proteins targets of ligands in complex biological mixtures. Knowing the false-positive rate of protein target discovery in proteome-wide SPROX experiments is important for the correct interpretation of results. Reported here are the results of a control SPROX experiment in which chemical denaturation data is obtained on the proteins in two samples that originated from the same yeast lysate, as would be done in a typical SPROX experiment except that one sample would be spiked with the test ligand. False-positive rates of 1.2-2.2 % and analysis of the isobaric mass tag (e.g., iTRAQ®) reporter ions used for peptide quantitation. Our results also suggest that technical replicates can be used to effectively eliminate such false positives that result from this random error, as is demonstrated in a SPROX experiment to identify yeast protein targets of the drug, manassantin A. The impact of ion purity in the tandem mass spectral analyses and of background oxidation on the false-positive rate of protein target discovery using SPROX is also discussed.

Application of tandem accelerator mass spectrometor to the chronological study of archaeological samples on Ryukyu Islands

International Nuclear Information System (INIS)

Taira, Hatsuo; Higa, Kenichi; Nakai, Nobuyuki; Nakamura, Toshio.

1987-01-01

Along with the urbanization of rural areas on Ryukyu Islands, many shell mounds and pre-historic sites have been found in resent years. Chrological studies of shell samples from these mounds will lead to the better understanding of cultural background for the pre-historic human activities on the Ryukyu Islands. C-14 dating by beta counting is the common method to obtain the ages of the archaeological samples. It is, however, very limitted in obtaining the absolute ages by the above mehtod due to the large sample sizes required and time consuming. There are many newly obtained archaeological samples left unstudied in detail. The alternate is a method called Tandem Accelerator Mass Spectrometer (AMS) installed at Nagoya University, which is composed of the tandem type accelerator to measure very low concentration of C-14 in archaeological samples. The system has been designed particularly to measure the radio-carbon and has advantages of being small sample size and very little time consuming for C-14 measurement as compared with the beta counting. It is the aim of this work to apply the above AMS for obtaining the absolute ages of the archaeological samples. The results agreed well with those estimated by the Erthenware method (relative method of dating), which ranged from 500 to 6000 y.b.p. The results may be helpful for the chronological arrangement of the samples and for the understanding of pre-historical human activities on the Ryukyu Islands. (author)

Analysis of perfluoroalkyl substances in cord blood by turbulent flow chromatography coupled to tandem mass spectrometry

International Nuclear Information System (INIS)

Llorca, Marta; Pérez, Francisca; Farré, Marinella; Agramunt, Sílvia; Kogevinas, Manolis; Barceló, Damià

2012-01-01

A fast on-line analytical method based on turbulent flow chromatography (TFC) in combination with tandem mass spectrometry has been applied for the first time for the analysis of eighteen perfluoroalkyl substances (PFASs), in cord blood. A simple and rapid sample pre-treatment was optimised consisting on protein precipitation of 100 μL of sample with acetonitrile (1:1) followed by centrifugation during 10 min. The method was adapted to be sensitive enough and robust with minimum sample injection volume requirements (20 μL). The optimised methodology presented method limits of detection (MLOD) between 0.031 and 0.76 μg/L, detection capabilities (CCα) in the range between 0.005 and 0.99 μg/L and decision limits (CCβ) ranging from 0.006 to 1.16 μg/L. The recoveries in blank blood were calculated by spiking experiments with a mixture of 18 PFASs and established between 70 and 126% for most of compounds. Isotopic dilution was carried out for quantification of selected analytes. In-house validation of this new approach was carried out according to the requirements in the 2002/657/EC Decision. Finally the good applicability of this new approach was proved by the analysis of 60 cord blood samples from two different Mediterranean cities, Barcelona (Spain) and Heraklion (Greece). Ions perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were found at highest concentration and the more frequently compounds were PFHxS, PFOS and perfluorooctanoic acid (PFOA). The newly developed method proved to be suitable for large-scale epidemiologic studies, and to the data on PFASs exposure during pregnancy. -- Highlights: ► An on-line method has been developed for the analysis of 18 perfluoroalkyl substances. ► The method is based on turbulent flow chromatography tandem mass spectrometry. ► The method was applied in 60 cord blood samples from 2 Mediterranean cities. ► Acidic compounds were more frequently found and the method was proved to be suitable for

Analysis of perfluoroalkyl substances in cord blood by turbulent flow chromatography coupled to tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Llorca, Marta; Perez, Francisca [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Farre, Marinella, E-mail: mfuqam@cid.csic.es [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Agramunt, Silvia [Centre for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); IMIM (Hospital del Mar Research Institute), Barcelona (Spain); Kogevinas, Manolis [Centre for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); IMIM (Hospital del Mar Research Institute), Barcelona (Spain); CIBER Epidemiologia y Salud Publica (CIBERESP), Barcelona (Spain); National School of Public Health, Athens (Greece); Barcelo, Damia [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Catalan Institute for Water Research (ICRA), Girona (Spain); King Saud University, Riyadh (Saudi Arabia)

2012-09-01

A fast on-line analytical method based on turbulent flow chromatography (TFC) in combination with tandem mass spectrometry has been applied for the first time for the analysis of eighteen perfluoroalkyl substances (PFASs), in cord blood. A simple and rapid sample pre-treatment was optimised consisting on protein precipitation of 100 {mu}L of sample with acetonitrile (1:1) followed by centrifugation during 10 min. The method was adapted to be sensitive enough and robust with minimum sample injection volume requirements (20 {mu}L). The optimised methodology presented method limits of detection (MLOD) between 0.031 and 0.76 {mu}g/L, detection capabilities (CC{alpha}) in the range between 0.005 and 0.99 {mu}g/L and decision limits (CC{beta}) ranging from 0.006 to 1.16 {mu}g/L. The recoveries in blank blood were calculated by spiking experiments with a mixture of 18 PFASs and established between 70 and 126% for most of compounds. Isotopic dilution was carried out for quantification of selected analytes. In-house validation of this new approach was carried out according to the requirements in the 2002/657/EC Decision. Finally the good applicability of this new approach was proved by the analysis of 60 cord blood samples from two different Mediterranean cities, Barcelona (Spain) and Heraklion (Greece). Ions perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were found at highest concentration and the more frequently compounds were PFHxS, PFOS and perfluorooctanoic acid (PFOA). The newly developed method proved to be suitable for large-scale epidemiologic studies, and to the data on PFASs exposure during pregnancy. -- Highlights: Black-Right-Pointing-Pointer An on-line method has been developed for the analysis of 18 perfluoroalkyl substances. Black-Right-Pointing-Pointer The method is based on turbulent flow chromatography tandem mass spectrometry. Black-Right-Pointing-Pointer The method was applied in 60 cord blood samples from 2 Mediterranean cities

DNA radio-induced tandem lesions: formation, introduction in oligonucleotides and repair

International Nuclear Information System (INIS)

Bourdat, Anne-Gaelle

2000-01-01

Cell killing induced by excited photosensitizers, ionizing radiation or radiomimetic drugs can not be only explained by the formation of single DNA lesions. Thus, multiply damaged sites, are likely to have harmful biological consequences. One example of tandem base damage induced by ".OH radical in X-irradiated aqueous solution of DNA oligomers is N-(2-deoxy-β-D-erythro-pentofuranosyl)-formyl-amine (dβF)/8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo). In order to investigate the biological significance of such a tandem lesion, both 8-oxodGuo and dβF were introduced in synthetic oligonucleotides at vicinal positions using the solid phase phosphoramidite method with the 'Pac phosphoramidite' chemistry. The purity of the synthetic DNA fragments and the integrity of modified nucleosides was confirmed using different complementary techniques: HPLC, PAGE, ESI MS, MALDI-TOF MS and capillary electrophoresis. Using the above synthetic substrates, investigations were carried out in order to determine the substrate specificity and the excision mechanism of three glycosylases involved in the base excision repair pathway: endonuclease III, Fpg and yOggl. Both tandem lesions were substrates for the BER enzymes. However, the tandem lesion are not completely excised by the repair enzymes. The rates of excision as inferred from the determination of the ratios of Vm/Km Michaelis kinetics constants were not found to be significantly affected by the presence of the tandem lesions. MALDI-TOF mass spectrometry was used in order to gain insights into mechanistic aspects of oligonucleotide cleavage by the BER enzymes. During in vitro DNA synthesis by Taq DNA polymerase, Klenow fragment exo- and DNA polymerase β, tandem base damage were found to block the progression of the enzymes. Finally, the level of tandem base damage in the DNA exposed to γ-ray using the liquid chromatography coupled to electro-spray ionization tandem mass spectrometry was determined. Both dβF-8-oxodGuo and 8

Observation of endoplasmic reticulum tubules via TOF-SIMS tandem mass spectrometry imaging of transfected cells.

Science.gov (United States)

Chini, Corryn E; Fisher, Gregory L; Johnson, Ben; Tamkun, Michael M; Kraft, Mary L

2018-02-26

Advances in three-dimensional secondary ion mass spectrometry (SIMS) imaging have enabled visualizing the subcellular distributions of various lipid species within individual cells. However, the difficulty of locating organelles using SIMS limits efforts to study their lipid compositions. Here, the authors have assessed whether endoplasmic reticulum (ER)-Tracker Blue White DPX ® , which is a commercially available stain for visualizing the endoplasmic reticulum using fluorescence microscopy, produces distinctive ions that can be used to locate the endoplasmic reticulum using SIMS. Time-of-flight-SIMS tandem mass spectrometry (MS 2 ) imaging was used to identify positively and negatively charged ions produced by the ER-Tracker stain. Then, these ions were used to localize the stain and thus the endoplasmic reticulum, within individual human embryonic kidney cells that contained higher numbers of endoplasmic reticulum-plasma membrane junctions on their surfaces. By performing MS 2 imaging of selected ions in parallel with the precursor ion (MS 1 ) imaging, the authors detected a chemical interference native to the cell at the same nominal mass as the pentafluorophenyl fragment from the ER-Tracker stain. Nonetheless, the fluorine secondary ions produced by the ER-Tracker stain provided a distinctive signal that enabled locating the endoplasmic reticulum using SIMS. This simple strategy for visualizing the endoplasmic reticulum in individual cells using SIMS could be combined with existing SIMS methodologies for imaging intracellular lipid distribution and to study the lipid composition within the endoplasmic reticulum.

A column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry method to determine anandamide and 2-arachidonoylglycerol in plasma samples.

Science.gov (United States)

Marchioni, Camila; de Souza, Israel Donizeti; Grecco, Caroline Fernandes; Crippa, José Alexandre; Tumas, Vitor; Queiroz, Maria Eugênia Costa

2017-05-01

This study reports a fast, sensitive, and selective column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine the endocannabinoids (eCBs), anandamide (AEA), and 2-arachidonoylglycerol (2-AG) in plasma samples. This bidimensional system used a restricted access media column (RP-8 ADS, 25 mm × 4 mm × 25 μM) in the first dimension and a core-shell Kinetex C18 (100 mm × 2, 1.7 mm × 1 μM) column in the second dimension, followed by detection in a mass spectrometer triple quadrupole (multiple reactions monitoring mode) operating in the positive mode. RP-8 ADS was used for trace enrichment of eCBs (reverse phase partitioning) and macromolecular matrix size exclusion; the core-shell column was used for the chromatographic separation. The column switching UHPLC-MS/MS method presented a linear range spanning from 0.1 ng mL -1 (LOQ) to 6 ng mL -1 for AEA and from 0.04 ng mL -1 (LOQ) to 10 ng mL -1 for 2-AG. Excluding the LLOQ values, the precision assays provided coefficients of variation lower than 8% and accuracy with relative standard error values lower than 14%. Neither carryover nor matrix effects were detected. This high-throughput column switching method compared to conventional methods is time saving as it involves fewer steps, consumes less solvent, and presents lower LLOQ. The column switching UHPLC-MS/MS method was successfully applied to determine AEA and 2-AG in plasma samples obtained from Alzheimer's disease patients. Graphical abstract A column switching ultra high-performance liquid chromatography-tandem mass spectrometry method using RP-8 ADS column and core shell column to determine endocannabinoids in plasma samples.

New calibration methodology for calorimetric determination of isobaric thermal expansivity of liquids as a function of temperature and pressure

Energy Technology Data Exchange (ETDEWEB)

Navia, Paloma; Troncoso, Jacobo [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain)], E-mail: romani@uvigo.es

2008-11-15

A new method for determining isobaric thermal expansivity of liquids as a function of temperature and pressure through calorimetric measurements against pressure is described. It is based on a previously reported measurement technique, but due to the different kind of calorimeter and experimental set up, a new calibration procedure was developed. Two isobaric thermal expansivity standards are needed; in this work, with a view on the quality of the available literature data, hexane and water are chosen. The measurements were carried out in the temperature and pressure intervals (278.15 to 348.15) K and (0.5 to 55) MPa for a set of liquids, and experimental values are compared with the available literature data in order to evaluate the precision of the experimental procedure. The analysis of the results reveals that the proposed methodology is highly accurate for isobaric thermal expansivity determination, and it allows obtaining a precise characterisation of the temperature and pressure dependence of this thermodynamic coefficient.

New calibration methodology for calorimetric determination of isobaric thermal expansivity of liquids as a function of temperature and pressure

International Nuclear Information System (INIS)

Navia, Paloma; Troncoso, Jacobo; Romani, Luis

2008-01-01

A new method for determining isobaric thermal expansivity of liquids as a function of temperature and pressure through calorimetric measurements against pressure is described. It is based on a previously reported measurement technique, but due to the different kind of calorimeter and experimental set up, a new calibration procedure was developed. Two isobaric thermal expansivity standards are needed; in this work, with a view on the quality of the available literature data, hexane and water are chosen. The measurements were carried out in the temperature and pressure intervals (278.15 to 348.15) K and (0.5 to 55) MPa for a set of liquids, and experimental values are compared with the available literature data in order to evaluate the precision of the experimental procedure. The analysis of the results reveals that the proposed methodology is highly accurate for isobaric thermal expansivity determination, and it allows obtaining a precise characterisation of the temperature and pressure dependence of this thermodynamic coefficient

Rapid Screening of Bovine Milk Oligosaccharides in a Whey Permeate Product and Domestic Animal Milks by Accurate Mass Database and Tandem Mass Spectral Library

Science.gov (United States)

Lee, Hyeyoung; Cuthbertson, Daniel J.; Otter, Don E.; Barile, Daniela

2018-01-01

A bovine milk oligosaccharide (BMO) library, prepared from cow colostrum, with 34 structures was generated and used to rapidly screen oligosaccharides in domestic animal milks and a whey permeate powder. The novel library was entered into a custom Personal Compound Database and Library (PCDL) and included accurate mass, retention time, and tandem mass spectra. Oligosaccharides in minute-sized samples were separated using nanoliquid chromatography (nanoLC) coupled to a high resolution and sensitive quadrupole-Time of Flight (Q-ToF) MS system. Using the PCDL, 18 oligosaccharides were found in a BMO-enriched product obtained from whey permeate processing. The usefulness of the analytical system and BMO library was further validated using milks from domestic sheep and buffaloes. Through BMO PCDL searching, 15 and 13 oligosaccharides in the BMO library were assigned in sheep and buffalo milks, respectively, thus demonstrating significant overlap between oligosaccharides in bovine (cow and buffalo) and ovine (sheep) milks. This method was shown to be an efficient, reliable, and rapid tool to identify oligosaccharide structures using automated spectral matching. PMID:27428379

Identification of the Related Substances in Ampicillin Capsule by Rapid Resolution Liquid Chromatography Coupled with Electrospray Ionization Tandem Mass Spectrometry

Directory of Open Access Journals (Sweden)

Lei Zhang

2014-01-01

Full Text Available Rapid Resolution Liquid Chromatography coupled with Electrospray Ionization Tandem Mass Spectrometry (RRLC-ESI-MSn was used to separate and identify related substances in ampicillin capsule. The fragmentation behaviors of related substances were used to identify their chemical structures. Finally, a total of 13 related substances in ampicillin capsule were identified, including four identified components for the first time and three groups of isomers on the basis of the exact mass, fragmentation behaviors, retention time, and chemical structures in the literature. This study avoided time-consuming and complex chemosynthesis of related substances of ampicillin and the results could be useful for the quality control of ampicillin capsule to guarantee its safety in clinic. In the meantime, it provided a good example for the rapid identification of chemical structures of related substances of drugs.

Determination of low-level acrylamide in drinking water by liquid chromatography/tandem mass spectrometry.

Science.gov (United States)

Lucentini, Luca; Ferretti, Emanuele; Veschetti, Enrico; Achene, Laura; Turrio-Baldassarri, Luigi; Ottaviani, Massimo; Bogialli, Sara

2009-01-01

A simple and sensitive liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method has been developed and validated to confirm and quantify acrylamide monomer (AA) in drinking water using [13C3] acrylamide as internal standard (IS). After a preconcentration by solid-phase extraction with spherical activated carbon, analytes were chromatographed on IonPac ICE-AS1 column (9 x 250 mm) under isocratic conditions using acetonitrile-water-0.1 M formic acid (43 + 52 + 5, v/v/v) as the mobile phase. Analysis was achieved using a triple-quadrupole mass analyzer equipped with a turbo ion spray interface. For confirmation and quantification of the analytes, MS data acquisition was performed in the multireaction monitoring mode, selecting 2 precursor ion to product ion transitions for both AA and IS. The method was validated for linearity, sensitivity, accuracy, precision, extraction efficiency, and matrix effect. Linearity in tap water was observed over the concentration range 0.1-2.0 microg/L. Limits of detection and quantification were 0.02 and 0.1 microg/L, respectively. Interday and intraday assays were performed across 3 validation levels (0.1, 0.5, and 1.5 microg/L). Accuracy (as mean recovery) ranged from 89.3 to 96.2% with relative standard deviation water in compliance with European Union and U.S. Environmental Protection Agency standards.

Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Tarkowski, Petr, E-mail: petr.tarkowski@upol.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Biochemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Vaclavikova, Katerina, E-mail: katka.vaclavik@seznam.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Biochemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Novak, Ondrej, E-mail: ondrej.novak@upol.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Pertry, Ine, E-mail: ine.pertry@ugent.BE [Department of Plant Biotechnology and Genetics, Ghent University, K.L.Ledeganckstraat 35, B-9000 Gent (Belgium); Hanus, Jan, E-mail: helehan@seznam.cz [Isotope Laboratory, Institute of Experimental Botany ASCR, Videnska 1083, 142 20 Prague (Czech Republic); Whenham, Robert [Apex Organics, Devon, England (United Kingdom); Vereecke, Danny, E-mail: danny.vereecke@hogent.BE [Department of Plant Production, University College Ghent, Ghent University, Schoonmeersstraat 52, B-9000 Gent (Belgium); Sebela, Marek, E-mail: marek.sebela@upol.cz [Department of Biochemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Strnad, Miroslav, E-mail: miroslav.strnad@upol.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic)

2010-11-08

A sensitive and reliable high-performance liquid chromatographic method with tandem mass spectrometric detection has been developed and used for the determination of 2-methylthio-cytokinin derivatives produced by the phytopathogenic actinomycete Rhodococcus fascians. The cultivation medium containing secreted cytokinins was concentrated and subjected to a solid-phase extraction (C18 and ion-exchange). The purified samples were further separated and analyzed by HPLC-ESI-MS/MS. This allowed to achieve chromatographic resolution of six highly hydrophobic cytokinin species including 2-methylthio-isopentenyladenine, 2-methylthio-isopentenyladenosine, 2-methylthio-trans-zeatin and 2-methylthio-trans-zeatin riboside and their cis-isomers when a reversed-phase chromatographic column (C4) and a mobile phase consisting of acetonitrile and 20 mM ammonium formate, pH 5, were used. Quantification was performed by a standard isotope dilution method using a multiple-reaction monitoring (MRM) mode. In the MRM mode, limits of detection reached 20-30 fmol and linear ranges spanned four orders of magnitude. Recovery values were between 35% and 65% and the analytical accuracy between 95% and 149%. The proposed bioanalytical method, which takes advantage of effective chromatographic separation of six 2-methyltio-derivatives (including isomers of zeatin-type cytokinins) and sensitive mass spectrometric detection, may become useful for plant biologists studying the significance of these substances in plant-microbe interactions.

Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

International Nuclear Information System (INIS)

Tarkowski, Petr; Vaclavikova, Katerina; Novak, Ondrej; Pertry, Ine; Hanus, Jan; Whenham, Robert; Vereecke, Danny; Sebela, Marek; Strnad, Miroslav

2010-01-01

A sensitive and reliable high-performance liquid chromatographic method with tandem mass spectrometric detection has been developed and used for the determination of 2-methylthio-cytokinin derivatives produced by the phytopathogenic actinomycete Rhodococcus fascians. The cultivation medium containing secreted cytokinins was concentrated and subjected to a solid-phase extraction (C18 and ion-exchange). The purified samples were further separated and analyzed by HPLC-ESI-MS/MS. This allowed to achieve chromatographic resolution of six highly hydrophobic cytokinin species including 2-methylthio-isopentenyladenine, 2-methylthio-isopentenyladenosine, 2-methylthio-trans-zeatin and 2-methylthio-trans-zeatin riboside and their cis-isomers when a reversed-phase chromatographic column (C4) and a mobile phase consisting of acetonitrile and 20 mM ammonium formate, pH 5, were used. Quantification was performed by a standard isotope dilution method using a multiple-reaction monitoring (MRM) mode. In the MRM mode, limits of detection reached 20-30 fmol and linear ranges spanned four orders of magnitude. Recovery values were between 35% and 65% and the analytical accuracy between 95% and 149%. The proposed bioanalytical method, which takes advantage of effective chromatographic separation of six 2-methyltio-derivatives (including isomers of zeatin-type cytokinins) and sensitive mass spectrometric detection, may become useful for plant biologists studying the significance of these substances in plant-microbe interactions.

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

Directory of Open Access Journals (Sweden)

You-Bo Zhang

2016-03-01

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

The transmission theory of electrostatic analyzer in six dimensional phase space and the concept design of a supersensitive mass spectrometer beam line for HI-13 tandem accelerator

International Nuclear Information System (INIS)

Guan Xialing; Cao Qingxi; Zhang Jie; Ye Jingping

1986-01-01

It follows from the motion equations of charged particle in curvilinear coordinates system that the transfer matrix of electrostatic analyzer was derived in six dimensional phase space. In accordance with these matrixes, the concept design of the supersensitive mass spectrometer beam line for HI-13 tandem accelerator was calculated

Fuel Application Efficiency in Ideal Cycle of Gas Turbine Plant with Isobaric Heat Supply

Directory of Open Access Journals (Sweden)

A. P. Nesenchuk

2013-01-01

Full Text Available The paper reveals expediency to use in prospect fuels with maximum value  Qнр∑Vi and minimum theoretical burning temperature in order to obtain maximum efficiency of the ideal cycle in GTP with isobaric heat supply.

Age trends in estradiol and estrone levels measured using liquid chromatography tandem mass spectrometry in community-dwelling men of the Framingham Heart Study.

Science.gov (United States)

Jasuja, Guneet Kaur; Travison, Thomas G; Davda, Maithili; Murabito, Joanne M; Basaria, Shehzad; Zhang, Anqi; Kushnir, Mark M; Rockwood, Alan L; Meikle, Wayne; Pencina, Michael J; Coviello, Andrea; Rose, Adam J; D'Agostino, Ralph; Vasan, Ramachandran S; Bhasin, Shalender

2013-06-01

Age trends in estradiol and estrone levels in men and how lifestyle factors, comorbid conditions, testosterone, and sex hormone-binding globulin affect these age trends remain poorly understood, and were examined in men of the Framingham Heart Study. Estrone and estradiol concentrations were measured in morning fasting samples using liquid chromatography tandem mass spectrometry in men of Framingham Offspring Generation. Free estradiol was calculated using a law of mass action equation. There were 1,461 eligible men (mean age [±SD] 61.1±9.5 years and body mass index [BMI] 28.8±4.5kg/m(2)). Total estradiol and estrone were positively associated with age, but free estradiol was negatively associated with age. Age-related increase in total estrone was greater than that in total estradiol. Estrone was positively associated with smoking, BMI, and testosterone, and total and free estradiol with diabetes, BMI, testosterone, and comorbid conditions; additionally, free estradiol was associated negatively with smoking. Collectively, age, BMI, testosterone, and other health and behavioral factors explained only 18% of variance in estradiol, and 9% of variance in estrone levels. Men in the highest quintile of estrone levels had significantly higher age and BMI, and a higher prevalence of smoking, diabetes, and cardiovascular disease than others, whereas those in the highest quintile of estradiol had higher BMI than others. Total estrone and estradiol levels in men, measured using liquid chromatography tandem mass spectrometry, revealed significant age-related increases that were only partially accounted for by cross-sectional differences in BMI, diabetes status, and other comorbidities and health behaviors. Longitudinal studies are needed to confirm these findings.

Characterization of Isomeric Glycans by Reversed Phase Liquid Chromatography-Electronic Excitation Dissociation Tandem Mass Spectrometry

Science.gov (United States)

Tang, Yang; Wei, Juan; Costello, Catherine E.; Lin, Cheng

2018-04-01

The occurrence of numerous structural isomers in glycans from biological sources presents a severe challenge for structural glycomics. The subtle differences among isomeric structures demand analytical methods that can provide structural details while working efficiently with on-line glycan separation methods. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool for mixture analysis, the commonly utilized collision-induced dissociation (CID) method often does not generate a sufficient number of fragments at the MS2 level for comprehensive structural characterization. Here, we studied the electronic excitation dissociation (EED) behaviors of metal-adducted, permethylated glycans, and identified key spectral features that could facilitate both topology and linkage determinations. We developed an EED-based, nanoscale, reversed phase (RP)LC-MS/MS platform, and demonstrated its ability to achieve complete structural elucidation of up to five structural isomers in a single LC-MS/MS analysis. [Figure not available: see fulltext.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-11-29

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

Characterization of the limonene oxidation products with liquid chromatography coupled to the tandem mass spectrometry

Science.gov (United States)

Witkowski, Bartłomiej; Gierczak, Tomasz

2017-04-01

Composition of the secondary organic aerosol (SOA) generated during ozonolysis of limonene was investigated with liquid chromatography coupled to the negative electrospray ionization (ESI), quadrupole tandem mass spectrometry (MS/MS) as well as high resolution Time-of-Flight mass spectrometry. Aerosol was generated in the flow-tube reactor. HR-MS/MS analysis allowed for proposing structures for the several up-to-date unknown limonene oxidation products. In addition to the low MW limonene oxidation products, significant quantities of oligomers characterized by elemental compositions: C19H30O5, C18H28O6, C19H28O7, C19H30O7 and C20H34O9 were detected in the SOA samples. It was concluded that these compounds are most likely esters, aldol reaction products and/or hemiacetals. In addition to detailed study of the limonene oxidation products, the reaction time as well as initial ozone concentration impact on the limonene SOA composition was investigated. The relative intensities of the two esters of the limonic acid and 7-hydroxy limononic acid increased as a result of lowering the initial ozone concentration and shortening the reaction time, indicating that esterification may be an important oligomerization pathway during limonene SOA formation.

Quantification of γ-Aminobutyric Acid in Cerebrospinal Fluid Using Liquid Chromatography-Electrospray Tandem Mass Spectrometry.

Science.gov (United States)

Arning, Erland; Bottiglieri, Teodoro

2016-01-01

We describe a simple stable isotope dilution method for accurate and precise measurement of γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter in human cerebrospinal fluid (CSF) as a clinical diagnostic test. Determination of GABA in CSF (50 μL) was performed utilizing high performance liquid chromatography coupled with electrospray positive ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analysis of free and total GABA requires two individual sample preparations and mass spectrometry analyses. Free GABA in CSF is determined by a 1:2 dilution with internal standard (GABA-D2) and injected directly onto the HPLC-ESI-MS/MS system. Determination of total GABA in CSF requires additional sample preparation in order to hydrolyze all the bound GABA in the sample to the free form. This requires hydrolyzing the sample by boiling in acidic conditions (hydrochloric acid) for 4 h. The sample is then further diluted 1:10 with a 90 % acetonitrile/0.1 % formic acid solution and injected into the HPLC-ESI-MS/MS system. Each assay is quantified using a five-point standard curve and is linear from 6 nM to 1000 nM and 0.63 μM to 80 μM for free and total GABA, respectively.

Characterization of N-Succinylation of L-Lysylphosphatidylglycerol in Bacillus subtilis Using Tandem Mass Spectrometry

Science.gov (United States)

Atila, Metin; Katselis, George; Chumala, Paulos; Luo, Yu

2016-10-01

Phospholipids generally dominate in bacterial lipids. The negatively charged nature of phospholipids renders bacteria susceptible to cationic antibiotic peptides. In comparison with Gram-negative bacteria, Gram-positive bacteria in general have much less zwitterionic phosphatidylethanolamine. However, they are known for producing aminoacylated phosphatidylglycerol (PG), especially positively charged l-lysyl-PG, which is catalyzed by lysyl-PG synthase MprF, which appears to have a broad range of specificity for l-aminoacyl transfer RNAs. In addition, many Gram-positive bacteria also have a dlt-gene-coded d-alanylation pathway for lipoteichoic acids and wall teichoic acids covalently attached to a glycolipid or peptidoglycan. d-Alanylation also masks the dominant negative charge of the phosphate-rich polymers of teichoic acids. Using mass spectrometry, we have recently observed that precursor scans in negative mode for deprotonated amino acid fragments were most sensitive for ester-linked amino acids. Such a scan for precursors generating an m/ z 145 lysyl anion revealed lysyl-PG as well as an additional species 100 m/ z units greater than lysyl-PG. This unexpected species corresponded precisely to the expected mass of N-succinylated lysyl-PG. Tandem mass spectrometry revealed a precise match to the fragmentation pattern of this putative new species. PG, lysyl-PG, and N-succinyl-lysyl-PG may form a complete loop of charge reversal from -1 to +1 and then back to -1. Analogous charge reversal by N-succinylation of lysine residues in the bacterial as well as eukaryotic proteomes has been recently discovered as a major posttranslational modification. Such modification in bacterial lipids is possibly catalyzed by an enzyme homologous to the enzymes that modify lysine residues in proteins.

Densities, isobaric thermal expansion coefficients and isothermal compressibilities of linear alkylbenzene

International Nuclear Information System (INIS)

Zhou, X; Zhang, Z Y; Zhang, Q M; Liu, Q; Ding, Y Y; Zhou, L; Cao, J

2015-01-01

We report the measurements of the densities of linear alkylbenzene at three temperatures over 4 to 23 °C with pressures up to 10 MPa. The measurements have been analysed to yield the isobaric thermal expansion coefficients and, so far for the first time, isothermal compressibilities of linear alkylbenzene. Relevance of results for current generation (i.e., Daya Bay) and next generation (i.e. JUNO) large liquid scintillator neutrino detectors are discussed. (paper)

Urinary free cortisol assessment by liquid chromatography tandem mass spectrometry: a case study of ion suppression due to unacquainted administration of piperacillin

Science.gov (United States)

Danese, Elisa; Salvagno, Gian Luca; Guzzo, Alessandra; Scurati, Samuele; Fava, Cristiano; Lippi, Giuseppe

2017-01-01

Introduction Liquid chromatography coupled to atmospheric pressure ionization tandem mass spectrometry (LC-ESI-MS/MS) is currently considered the reference method for quantitative determination of urinary free cortisol (UFC). One of the major drawbacks of this measurement is a particular form of matrix effect, conventionally known as ion suppression. Materials and methods We describe here the case of a 66-year-old-patient referred to the daily service of general medicine for intravenous antibiotic administration due to a generalized Staphylococcus aureus infection and for routine 24 hours UFC monitoring in the setting of glucocorticoid replacement therapy. Results The observation of 10-fold decrease of internal standard of cortisol signal led us to hypothesize the presence of an ion suppression effect due to a co-eluting endogenous compound. Screening analysis of tandem mass spectrometry (MS/MS) spectra of the interfering molecule, along with in vitro confirmation analyses, were suggestive of the presence of high concentration of piperacillin. The problem was then easily solved with minor modifications of the chromatographic technique. Conclusions According to our findings, antibiotic therapy with piperacillin/tazobactam should be regarded as an important interference in UFC assessment, which may potentially affect detection capability, precision and accuracy of this measurement. This case report emphasizes that accurate anamnesis and standardization of all phases of urine collection are essential aspects for preventing potential interference in laboratory testing. PMID:29180920

Tandem affinity purification of histones, coupled to mass spectrometry, identifies associated proteins and new sites of post-translational modification in Saccharomyces cerevisiae.

Science.gov (United States)

Valero, M Luz; Sendra, Ramon; Pamblanco, Mercè

2016-03-16

Histones and their post-translational modifications contribute to regulating fundamental biological processes in all eukaryotic cells. We have applied a conventional tandem affinity purification strategy to histones H3 and H4 of the yeast Saccharomyces cerevisiae. Mass spectrometry analysis of the co-purified proteins revealed multiple associated proteins, including core histones, which indicates that tagged histones may be incorporated to the nucleosome particle. Among the many other co-isolated proteins there are histone chaperones, elements of chromatin remodeling, of nucleosome assembly/disassembly, and of histone modification complexes. The histone chaperone Rtt106p, two members of chromatin assembly FACT complex and Psh1p, an ubiquitin ligase, were the most abundant proteins obtained with both H3-TAP and H4-TAP, regardless of the cell extraction medium stringency. Our mass spectrometry analyses have also revealed numerous novel post-translational modifications, including 30 new chemical modifications in histones, mainly by ubiquitination. We have discovered not only new sites of ubiquitination but that, besides lysine, also serine and threonine residues are targets of ubiquitination on yeast histones. Our results show the standard tandem affinity purification procedure is suitable for application to yeast histones, in order to isolate and characterize histone-binding proteins and post-translational modifications, avoiding the bias caused by histone purification from a chromatin-enriched fraction. Copyright © 2016 Elsevier B.V. All rights reserved.

Screening and quantitative determination of twelve acidic and neutral pharmaceuticals in whole blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry

DEFF Research Database (Denmark)

Simonsen, Kirsten Wiese; Steentoft, Anni; Buck, Maike

2010-01-01

. The method was fully validated for salicylic acid, paracetamol, phenobarbital, carisoprodol, meprobamate, topiramate, etodolac, chlorzoxazone, furosemide, ibuprofen, warfarin, and salicylamide. The method also tentatively includes thiopental, theophylline, piroxicam, naproxen, diclophenac, and modafinil......We describe a multi-method for simultaneous identification and quantification of 12 acidic and neutral compounds in whole blood. The method involves a simple liquid-liquid extraction, and the identification and quantification are performed using liquid chromatography-tandem mass spectrometry...

A high-performance liquid chromatography-tandem mass spectrometry method coupled with protein precipitation for determination of granisetron in human plasma and its application to a comparative pharmacokinetic study.

Science.gov (United States)

Zhou, Ying; Jiang, Ji; Hu, Pei; Wang, Hongyun

2014-12-01

A rapid, simple and validated method based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has been developed for the determination of granisetron in human plasma. Plasma samples were pre-purified by protein precipitation procedure. The chromatographic separation was achieved with Synergi Polar-RP (75 × 2 mm, 4 µm) column using a mixture of 5 mm pH4.0 ammonium formate and methanol (300:316, v/v) under isocratic conditions at a flow rate of 0.3 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. The analysis time was about 2.5 min. The method was fully validated over the concentration range 0.1-10 ng/mL. The lower limit of quantification was 0.1 ng/mL. Inter- and intra-batch precision was granisetron in Chinese healthy subjects. Copyright © 2014 John Wiley & Sons, Ltd.

Development of a dedicated peptide tandem mass spectral library for conservation science.

Science.gov (United States)

Fremout, Wim; Dhaenens, Maarten; Saverwyns, Steven; Sanyova, Jana; Vandenabeele, Peter; Deforce, Dieter; Moens, Luc

2012-05-30

In recent years, the use of liquid chromatography tandem mass spectrometry (LC-MS/MS) on tryptic digests of cultural heritage objects has attracted much attention. It allows for unambiguous identification of peptides and proteins, and even in complex mixtures species-specific identification becomes feasible with minimal sample consumption. Determination of the peptides is commonly based on theoretical cleavage of known protein sequences and on comparison of the expected peptide fragments with those found in the MS/MS spectra. In this approach, complex computer programs, such as Mascot, perform well identifying known proteins, but fail when protein sequences are unknown or incomplete. Often, when trying to distinguish evolutionarily well preserved collagens of different species, Mascot lacks the required specificity. Complementary and often more accurate information on the proteins can be obtained using a reference library of MS/MS spectra of species-specific peptides. Therefore, a library dedicated to various sources of proteins in works of art was set up, with an initial focus on collagen rich materials. This paper discusses the construction and the advantages of this spectral library for conservation science, and its application on a number of samples from historical works of art. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous determination of 14 active constituents of Shengjiang Xiexin decoction using ultrafast liquid chromatography coupled with electrospray ionization tandem mass spectrometry

Institute of Scientific and Technical Information of China (English)

Gang Peng; Huanyu Guan; Xiaoming Wang; Yue Shi

2017-01-01

An effective herbal medicinal prescription of Shengjiang Xiexin decoction (SXD) was used in treating the inflammatory bowel disease in clinic.In this study,an ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed to separate and to simultaneously determine 14 major active ingredients in SXD.Chromatographic separation was successfully accomplished on an Acquity BEH C18 (100 mm × 2.1 mm,1.7 μm) column using gradient elution with 0.1％ (v/v) formic acid water (A) and 0.1％ (v/v) formic acid in methanol (B).Negative and positive electrospray ionization tandem mass spectrometry was used to detect the 14 analytes using its selective reaction monitoring (SRM) mode.A good linear regression relationship for each analyte was obtained over the range from 3.88 ng/mL to 4080 ng/mL.The precision was evaluated by intra-and inter-day assays with a relative standard deviation (RSD) of less than 6.25％.The recovery measured at three concentration levels varied from 98.72％ to 103.47％.The overall limits of quantification (LOQ) ranged from 2.05 ng/mL to 4.72 ng/mL.The method was successfully implemented in the qualitative and quantitative analyses of the 14 chemical constituents in SXD.The results showed that the developed UFLC-MS/MS method was linear and accurate.The method could be used reliably as a quality control method for SXD.

Simultaneous determination of 14 active constituents of Shengjiang Xiexin decoction using ultrafast liquid chromatography coupled with electrospray ionization tandem mass spectrometry

Institute of Scientific and Technical Information of China (English)

Gang Peng; Huanyu Guan; Xiaoming Wang; Yue Shi

2017-01-01

An effective herbal medicinal prescription of Shengjiang Xiexin decoction(SXD) was used in treating the inflammatory bowel disease in clinic.In this study,an ultrafast liquid chromatography-tandem mass spectrometry(UFLC-MS/MS) method was developed to separate and to simultaneously determine14 major active ingredients in SXD.Chromatographic separation was successfully accomplished on an Acquity BEH C18(100 mm × 2.1 mm,1.7 μm) column using gradient elution with 0.1%(v/v) formic acid water(A) and 0.1%(v/v) formic acid in methanol(B).Negative and positive electrospray ionization tandem mass spectrometry was used to detect the 14 analytes using its selective reaction monitoring(SRM) mode.A good linear regression relationship for each analyte was obtained over the range from3.88 ng/mL to 4080 ng/mL.The precision was evaluated by intra-and inter-day assays with a relative standard deviation(RSD) of less than 6.25%.The recovery measured at three concentration levels varied from 98.72%to 103.47%.The overall limits of quantification(LOQ) ranged from 2.05 ng/mL to4.72 ng/mL.The method was successfully implemented in the qualitative and quantitative analyses of the14 chemical constituents in SXD.The results showed that the developed UFLC-MS/MS method was linear and accurate.The method could be used reliably as a quality control method for SXD.

Deciphering the structure of isomeric oligosaccharides in a complex mixture by tandem mass spectrometry: Photon activation with vacuum ultra-violet brings unique information and enables definitive structure assignment

Energy Technology Data Exchange (ETDEWEB)

Ropartz, David, E-mail: David.Ropartz@nantes.inra.fr [INRA, UR1268 Biopolymers Interactions Assemblies, F-44316 Nantes (France); Lemoine, Jérôme [Institut des Sciences Analytiques, UMR 5280, Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne cedex (France); Giuliani, Alexandre [Synchrotron SOLEIL, L’Orme des Merisiers, F-91190 Gif-sur-Yvette (France); UAR 1008 CEPIA, INRA, F-44316 Nantes (France); Bittebière, Yann [INRA, UR1268 Biopolymers Interactions Assemblies, F-44316 Nantes (France); Enjalbert, Quentin [Institut des Sciences Analytiques, UMR 5280, Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne cedex (France); Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne cedex (France); Antoine, Rodolphe; Dugourd, Philippe [Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne cedex (France); Ralet, Marie-Christine; Rogniaux, Hélène [INRA, UR1268 Biopolymers Interactions Assemblies, F-44316 Nantes (France)

2014-01-07

Graphical abstract: -- Highlights: •A complex mixture of methylated oligogalacturonans was fractionated by IP-RP-UHPLC. •Synchrotron-radiation in VUV range was used as an activation process for tandem MS. •VUV activation brought rich structural information compared to LE-CAD. •Resolution of more than 35 structures, including isomers, was successfully completed. -- Abstract: Carbohydrates have a wide variety of structures whose complexity and heterogeneity challenge the field of analytical chemistry. Tandem mass spectrometry, with its remarkable sensitivity and high information content, provides key advantages to addressing the structural elucidation of polysaccharides. Yet, classical fragmentation by collision-activated dissociation (CAD) in many cases fails to reach a comprehensive structural determination, especially when isomers have to be differentiated. In this work, for the first time, vacuum ultra-violet (VUV) synchrotron radiation is used as the activation process in tandem mass spectrometry of large oligosaccharides. Compared to low energy CAD (LE-CAD), photon activated dissociation brought more straightforward and valuable structural information. The outstanding feature was that complete series of informative ions were produced, with only minor neutral losses. Moreover, systematic fragmentation rules could be drawn thus facilitating the definitive assignments of fragment identities. As a result, most of the structures present in a complex mixture of oligogalacturonans could be comprehensively resolved, including many isomers differing in the position of methyl groups along the galacturonic acid backbone.

Proteomic Identification and Quantification of S-glutathionylation in Mouse Macrophages Using Resin-Assisted Enrichment and Isobaric Labeling

Energy Technology Data Exchange (ETDEWEB)

Su, Dian; Gaffrey, Matthew J.; Guo, Jia; Hatchell, Kayla E.; Chu, Rosalie K.; Clauss, Therese RW; Aldrich, Joshua T.; Wu, Si; Purvine, Samuel O.; Camp, David G.; Smith, Richard D.; Thrall, Brian D.; Qian, Weijun

2014-02-11

Protein S-glutathionylation (SSG) is an important regulatory posttranslational modification of protein cysteine (Cys) thiol redox switches, yet the role of specific cysteine residues as targets of modification is poorly understood. We report a novel quantitative mass spectrometry (MS)-based proteomic method for site-specific identification and quantification of S-glutathionylation across different conditions. Briefly, this approach consists of initial blocking of free thiols by alkylation, selective reduction of glutathionylated thiols and enrichment using thiol affinity resins, followed by on-resin tryptic digestion and isobaric labeling with iTRAQ (isobaric tags for relative and absolute quantitation) for MS-based identification and quantification. The overall approach was validated by application to RAW 264.7 mouse macrophages treated with different doses of diamide to induce glutathionylation. A total of 1071 Cys-sites from 690 proteins were identified in response to diamide treatment, with ~90% of the sites displaying >2-fold increases in SSG-modification compared to controls.. This approach was extended to identify potential SSG modified Cys-sites in response to H2O2, an endogenous oxidant produced by activated macrophages and many pathophysiological stimuli. The results revealed 364 Cys-sites from 265 proteins that were sensitive to S-glutathionylation in response to H2O2 treatment. These proteins covered a range of molecular types and molecular functions with free radical scavenging, and cell death and survival included as the most significantly enriched functional categories. Overall the results demonstrate that our approach is effective for site-specific identification and quantification of S-glutathionylated proteins. The analytical strategy also provides a unique approach to determining the major pathways and cell processes most susceptible to glutathionylation at a proteome-wide scale.

Precise determination of 40Ti mass by measuring the 40Sc isospin analogue state

International Nuclear Information System (INIS)

Liu Weiping; Hellstroem, M.; Collatz, R.; Benlliure, J.; Cortina, G.D.; Farget, F.; Grawe, H.; Hu, Z.; Iwasa, N.; Pfuetzner, M.; Roeckl, E.; Chulkov, L.; Piechaczek, A.; Raabe, R.; Reusen, I.; Vancraeynest, G.; Woehr, A.

2001-01-01

The mass of 40 Ti has been determined by using the isobaric multiplet mass equation method. The experimental data of the 40 Ti β-decay were used to determine the level of the isospin analogue state of 40 Sc. The ground-state mass excess and the Q EC value for 40 Ti were determined to be -9060 +- 12 keV and 11466 +- 13 keV, respectively

Intrathecal isobaric ropivacaine-fentanyl versus intrathecal isobaric bupivacaine-fentanyl for labor analgesia: A controlled comparative double-blinded study

Directory of Open Access Journals (Sweden)

Meenoti Pramod Potdar

2014-01-01

Full Text Available Context: Neuraxial analgesia and walking epidural is the popular method of practicing labor analgesia. The combination of local anesthetic and opioid is advantageous as it prolongs the duration of labor analgesia. Ropivacaine is the newer local anesthetic agent having lesser motor effects and toxic effects hence would be preferred for labor analgesia. Aims: The primary objective of the study was to assess the duration of analgesia of the intrathecal drug. The secondary objective was the assessment of onset, fixation of analgesia, motor weakness, ambulation, sedation, incidence of side-effects, maternal, and neonatal outcomes. Settings and Design: This is prospective, randomized, controlled, double-blinded, study of 120 patients consenting for labor analgesia. Subjects and Methods: A total of 120 primiparas with a singleton pregnancy in active labor who were given combined spinal epidural (CSE were included in the study. These patients were randomly allocated to three groups of 40 each and received CSE. Group F-received 25 μcg fentanyl intrathecally. Group BF-received 25 μcg fentanyl with 2.5 mg isobaric bupivacaine intrathecally. Group RF-received 25 μcg fentanyl with 2.5 mg isobaric ropivacaine intrathecally. Statistical Analysis Used: Correlations among different measurements were assessed using Pearson′s correlation coefficients, P <0.05 was considered to be statistically significant. Results: The three groups show comparable demographic data and obstetric parameters. The duration of spinal analgesia was significantly greater with Group RF 106.63 ± 17.99 min and Group BF 111.75 ± 23.58 min than the control Group F which was 60 ± 10.39 min with P = 0.001, but were comparable for Group BF and RF. The secondary outcome was comparable in all the three groups. Conclusions: The addition of bupivacaine or ropivacaine to fentanyl intrathecally increased duration and quality of analgesia, did not affect ambulation and bearing down. The

Simultaneous analysis of fourteen tertiary amine stimulants in human urine for doping control purposes by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry

International Nuclear Information System (INIS)

Lu Jianghai; Wang San; Dong Ying; Wang Xiaobing; Yang Shuming; Zhang Jianli; Deng Jing; Qin Yang; Xu Youxuan; Wu Moutian; Ouyang Gangfeng

2010-01-01

A method for the simultaneous screening and confirmation of the presence of fourteen tertiary amine stimulants in human urine by gas chromatography-mass spectrometry (GC-MS) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated. Solid phase extraction (SPE) and liquid-liquid extraction (LLE) approaches were utilized for the pre-treatment of the urine samples. The study indicated that the capillary temperature played a significant role in the signal abundances of the protonated molecules of cropropamide and crotethamide under positive ion electrospray ionization (ESI) conditions. In addition, comparison studies of two different pre-treatment approaches as well as the two ionization modes were conducted. The LODs of the developed method for all the analytes were lower than the minimum required performance limit (MRPL) as set forth in the World Anti-Doping Agency (WADA) technical document for laboratories. The human urine sample obtained after oral administration of prolintane.HCl was successfully analyzed by the developed method, which demonstrated the applicability and reliability of the method for routine doping control analysis.

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

International Nuclear Information System (INIS)

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

2009-01-01

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

Present status of tandem accelerator analysis facility in National Institute for Environmental Studies

Energy Technology Data Exchange (ETDEWEB)

Kume, Hiroshi; Shibata, Yasuyuki; Tanaka, Atsushi; Yoneda, Minoru; Kumamoto, Yuichiro; Uehiro, Takashi; Morita, Masatoshi [National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan)

1996-12-01

In National Institute for Environmental Studies, two types of tandem accelerator analysis facilities were able to be installed in September, 1995. One is the accelerator mass analysis exclusive equipment with a 5 MV tandem accelerator, and the other is the high energy ion beam analyzer, in which the surface analysis system is connected to a 1 MV tandem accelerator, mainly used for PIXE measurement. The accelerator mass analyzer can be roughly divided into four parts, that is, ion source and negative ion injection system, accelerator, high energy analysis system, minute amount isotope beam line and control system. These parts are briefly explained. The test measurement of carbon isotope ratio was carried out, but the results dispersed and unsatisfactory. As for the ion beam analyzer, the surface analysis system (RBS400) of Charles Evans and Associates is combined with a 1 MV PELETRON tandem accelerator (3SDH) of NEC, and these are described. This analyzer also is not in the state that the steady operation can be carried out. Slight leak occurred in the ion source. The countermeasures to both cases are in progress. (K.I.)

A review of electron-capture and electron-transfer dissociation tandem mass spectrometry in polymer chemistry

International Nuclear Information System (INIS)

Hart-Smith, Gene

2014-01-01

Graphical abstract: -- Highlights: •ECD and ETD can produce unique and diagnostically useful polymer ion fragmentation data. •The operating principles of ECD and ETD are discussed in relation to other dissociation techniques. •Key characteristics of ECD and ETD spectra, as observed from biological analytes, are discussed. •ECD and ETD analyses are compared to CID analyses for different classes of synthetic polymer. -- Abstract: Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community

Pulsed flow modulation two-dimensional comprehensive gas chromatography-tandem mass spectrometry with supersonic molecular beams.

Science.gov (United States)

Poliak, Marina; Fialkov, Alexander B; Amirav, Aviv

2008-11-07

Pulsed flow modulation (PFM) two-dimensional comprehensive gas chromatography (GC x GC) was combined with quadrupole-based mass spectrometry (MS) via a supersonic molecular beam (SMB) interface using a triple-quadrupole system as the base platform, which enabled tandem mass spectrometry (MS-MS). PFM is a simple GC x GC modulator that does not consume cryogenic gases while providing tunable second GC x GC column injection time for enabling the use of quadrupole-based mass spectrometry regardless its limited scanning speed. The 20-ml/min second column flow rate involved with PFM is handled, splitless, by the SMB interface without affecting the sensitivity. The combinations of PFM GC x GC-MS with SMB and PFM GC x GC-MS-MS with SMB were explored with the analysis of diazinon and permethrin in coriander. PFM GC x GC-MS with SMB is characterized by enhanced molecular ion and tailing-free fast ion source response time. It enables universal pesticide analysis with full scan and data analysis with reconstructed single ion monitoring on the enhanced molecular ion and another prominent high mass fragment ion. The elimination of the third fragment ion used in standard three ions method results in significantly reduced matrix interference. GC x GC-MS with SMB improves the GC separation, and thereby our ability for sample identification using libraries. GC-MS-MS with SMB provides better reduction (elimination) of matrix interference than GC x GC-MS. However, it is a target method, which is not always applicable. GC x GC-MS-MS does not seem to further reduce matrix interferences over GC-MS-MS and unlike GC x GC-MS, it is incompatible with library identification, but it is beneficial to have both GC x GC and MS-MS capabilities in the same system.

Quantification of rifampicin in human plasma and cerebrospinal fluid by a highly sensitive and rapid liquid chromatographic-tandem mass spectrometric method.

Science.gov (United States)

Srivastava, Abhishek; Waterhouse, David; Ardrey, Alison; Ward, Stephen A

2012-11-01

A highly sensitive and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method has been developed to measure the levels of the antitubercular drug rifampicin (RIF) in human plasma and cerebrospinal fluid (CSF). The analyte and internal standard (IS) were isolated from plasma and CSF by a simple organic solvent based precipitation of proteins followed by centrifugation. Detection was carried out by electrospray positive ionization mass spectrometry in the multiple-reaction monitoring (MRM) mode. The assay was linear in the concentration range 25-6400 ng/mL with intra- and inter-day precision of <7% and <8%, respectively. The validated method was applied to the study of RIF pharmacokinetics in human CSF and plasma over 25 h period after a 10 mg/kg oral dose. Copyright © 2012 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2015-10-01

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

Capillary zone electrophoresis-tandem mass spectrometry detects low concentration host cell impurities in monoclonal antibodies

Science.gov (United States)

Zhu, Guijie; Sun, Liangliang; Heidbrink-Thompson, Jennifer; Kuntumalla, Srilatha; Lin, Hung-yu; Larkin, Christopher J.; McGivney, James B.; Dovichi, Norman J.

2016-01-01

We have evaluated capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) for detection of trace amounts of host cell protein impurities in recombinant therapeutics. Compared to previously published procedures, we have optimized the buffer pH used in the formation of a pH junction to increase injection volume. We also prepared a five-point calibration curve by spiking twelve standard proteins into a solution of a human monoclonal antibody. A custom CZE-MS/MS system was used to analyze the tryptic digest of this mixture without depletion of the antibody. CZE generated a ~70 min separation window (~90 min total analysis duration) and ~300 peak capacity. We also analyzed the sample using ultra-performance liquid chromatography (UPLC)-MS/MS. CZE-MS/MS generated ~five times higher base peak intensity and more peptide identifications for low-level spiked proteins. Both methods detected all proteins spiked at the ~100 ppm level with respect to the antibody. PMID:26530276

LipidMatch: an automated workflow for rule-based lipid identification using untargeted high-resolution tandem mass spectrometry data.

Science.gov (United States)

Koelmel, Jeremy P; Kroeger, Nicholas M; Ulmer, Candice Z; Bowden, John A; Patterson, Rainey E; Cochran, Jason A; Beecher, Christopher W W; Garrett, Timothy J; Yost, Richard A

2017-07-10

Lipids are ubiquitous and serve numerous biological functions; thus lipids have been shown to have great potential as candidates for elucidating biomarkers and pathway perturbations associated with disease. Methods expanding coverage of the lipidome increase the likelihood of biomarker discovery and could lead to more comprehensive understanding of disease etiology. We introduce LipidMatch, an R-based tool for lipid identification for liquid chromatography tandem mass spectrometry workflows. LipidMatch currently has over 250,000 lipid species spanning 56 lipid types contained in in silico fragmentation libraries. Unique fragmentation libraries, compared to other open source software, include oxidized lipids, bile acids, sphingosines, and previously uncharacterized adducts, including ammoniated cardiolipins. LipidMatch uses rule-based identification. For each lipid type, the user can select which fragments must be observed for identification. Rule-based identification allows for correct annotation of lipids based on the fragments observed, unlike typical identification based solely on spectral similarity scores, where over-reporting structural details that are not conferred by fragmentation data is common. Another unique feature of LipidMatch is ranking lipid identifications for a given feature by the sum of fragment intensities. For each lipid candidate, the intensities of experimental fragments with exact mass matches to expected in silico fragments are summed. The lipid identifications with the greatest summed intensity using this ranking algorithm were comparable to other lipid identification software annotations, MS-DIAL and Greazy. For example, for features with identifications from all 3 software, 92% of LipidMatch identifications by fatty acyl constituents were corroborated by at least one other software in positive mode and 98% in negative ion mode. LipidMatch allows users to annotate lipids across a wide range of high resolution tandem mass spectrometry

Extending and refining the mass surface around $^{208}$Pb by high-precision Penning-trap mass spectrometry with ISOLTRAP

CERN Multimedia

Herfurth, F; Stora, T; Blaum, K; Beck, D; Kowalska, M; Schwarz, S; Stanja, J; Herlert, A J; Yamaguchi, T

We propose high-precision mass spectrometry of nuclides around the doubly magic $^{208}$Pb. On the neutron-rich side, we aim to extend the knowledge of Fr, At, Hg, and Au masses to study the robustness of the N = 126 shell closure and to provide mass data necessary for modeling the rapid-neutron-capture process. On the proton-rich side, we aim at high-resolution mass spectrometry of selected Au, At, and Fr isotopes to verify the predicted existence of very low-lying isomeric states. The proposal will make use of newly-available laser-ionization schemes for Au and At. Finally, the recently implemented multi-reflection time-of-flight mass separator for auxiliary isobaric purification now allows measurements which were not feasible before.

Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage

Directory of Open Access Journals (Sweden)

André Luiz da Costa MICHELOTTO

2015-01-01

Full Text Available The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1, with gutta-percha + Sealapex (G2, and with gutta-percha + AH Plus (G3. Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0, applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS. None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively, whereas G1 showed significantly higher values (mean: 105.2 ng mL-1. At 60 days, leakage values were 182.6 ng mL-1for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization

International Nuclear Information System (INIS)

Ropartz, David; Giuliani, Alexandre; Fanuel, Mathieu; Hervé, Cécile; Czjzek, Mirjam; Rogniaux, Hélène

2016-01-01

The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. - Highlights: • For the first time, XUV photon activation tandem MS was coupled to UHPLC. • The approach was used to characterize a complex mixture of biomolecules. • The MSMS duty cycle was compatible with elution times of UHPLC without compromised. • Minor species were characterized with an enhanced sensitivity and dynamic range. • These results broaden the application of the technique in many field of

Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization

Energy Technology Data Exchange (ETDEWEB)

Ropartz, David, E-mail: David.Ropartz@nantes.inra.fr [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Giuliani, Alexandre [Synchrotron SOLEIL, L' Orme des Merisiers, F-91190 Gif-sur-Yvette (France); UAR 1008 CEPIA, INRA, F-44316 Nantes (France); Fanuel, Mathieu [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Hervé, Cécile; Czjzek, Mirjam [Sorbonne Universités, Université Pierre et Marie Curie, Paris VI, CNRS, Integrative Biology of Marine Models, UMR 8227, Station Biologique, Place George Teissier, F29688 Roscoff Cedex (France); Rogniaux, Hélène [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France)

2016-08-24

The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. - Highlights: • For the first time, XUV photon activation tandem MS was coupled to UHPLC. • The approach was used to characterize a complex mixture of biomolecules. • The MSMS duty cycle was compatible with elution times of UHPLC without compromised. • Minor species were characterized with an enhanced sensitivity and dynamic range. • These results broaden the application of the technique in many field of

Examination of segmental average mass spectra from liquid chromatography-tandem mass spectrometric (LC-MS/MS) data enables screening of multiple types of protein modifications.

Science.gov (United States)

Liu, Nai-Yu; Lee, Hsiao-Hui; Chang, Zee-Fen; Tsay, Yeou-Guang

2015-09-10

It has been observed that a modified peptide and its non-modified counterpart, when analyzed with reverse phase liquid chromatography, usually share a very similar elution property [1-3]. Inasmuch as this property is common to many different types of protein modifications, we propose an informatics-based approach, featuring the generation of segmental average mass spectra ((sa)MS), that is capable of locating different types of modified peptides in two-dimensional liquid chromatography-mass spectrometric (LC-MS) data collected for regular protease digests from proteins in gels or solutions. To enable the localization of these peptides in the LC-MS map, we have implemented a set of computer programs, or the (sa)MS package, that perform the needed functions, including generating a complete set of segmental average mass spectra, compiling the peptide inventory from the Sequest/TurboSequest results, searching modified peptide candidates and annotating a tandem mass spectrum for final verification. Using ROCK2 as an example, our programs were applied to identify multiple types of modified peptides, such as phosphorylated and hexosylated ones, which particularly include those peptides that could have been ignored due to their peculiar fragmentation patterns and consequent low search scores. Hence, we demonstrate that, when complemented with peptide search algorithms, our approach and the entailed computer programs can add the sequence information needed for bolstering the confidence of data interpretation by the present analytical platforms and facilitate the mining of protein modification information out of complicated LC-MS/MS data. Copyright © 2015 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2006-11-03

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

[Determination of thyreostats in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry].

Science.gov (United States)

Lech, Rodziewicz; Jolanta, MasŁOwiecka; Anna, Sadowska; Halina, Car

2017-10-08

Five thyreostats (TSs), namely tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil, were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in positive electrospray ionization mode. Extraction and clean-up were achieved using a ChemElut cartridge with tert -butyl methyl ether, without a derivatization step. Separation was achieved on an Acquity UPLC SS T3 column. The mobile phase was acetonitrile and water containing 0.2% (v/v) formic acid. The mass spectrometer was operated in multiple reaction monitoring mode. Urine samples were spiked with TS solution at levels corresponding to 5, 10, 15, and 20 μg/L. The accuracy (internal standard corrected) ranged from 92% to 107%, with a repeatability precision (relative standard deviation, RSD) less than 15% for all five analytes. The RSDs within-laboratory reproducibility was less than 26%. The decision limits (CCα) and detection capabilities (CCβ) were obtained from a calibration curve and were in the ranges of 3.1-6.1 μg/L and 4.0-7.4 μg/L, respectively. The CCα and CCβ values were below the recommended concentration, which was set at 10 μg/L. The results show that the described method is suitable for the direct detection of TSs in bovine urine. This method can also be used to determine TSs in porcine urine.

Confirmation of congenital adrenal hyperplasia by adrenal steroid profiling of filter paper dried blood samples using ultra-performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Rossi, Claudia; Calton, Lisa; Brown, Heather A; Gillingwater, Scott; Wallace, A Michael; Petrucci, Francesca; Ciavardelli, Domenico; Urbani, Andrea; Sacchetta, Paolo; Morris, Michael

2011-04-01

The specificity of screening for congenital adrenal hyperplasia by direct measurement of 17-hydroxyprogesterone in filter paper dried blood spot samples by immunoassay is low and has a high false-positive rate. In order to reduce the false-positive rate of this test, we developed a rapid, robust, specific confirmatory procedure in which cortisol, 4-androstene-3,17-dione and 17-hydroxyprogesterone were measured simultaneously by ultra-performance liquid chromatography-tandem mass spectrometry. After extraction, samples were analysed by ultra-performance liquid chromatography-tandem mass spectrometry and 17-hydroxyprogesterone was quantified accurately. Other steroids were determined using stable deuterated internal standards. In total, 25 patient blood spot samples and 92 control samples were analysed. The assay was linear for 17-hydroxyprogesterone, with a coefficient of determination >0.997 and imprecision ≤ 6.5%. An upper limit of normal for 17-hydroxyprogester-one of 4.45 nmol/L was established by analysing a cohort of samples from unaffected newborns. In addition, a cut-off of 3.5 for the peak areas ratio (17-hydroxyprogesterone+4-androstene-3,17-dione)/cortisol, allows confirmation of the affected steroidogenic enzyme. A high throughput method for the detection of steroids related to congenital adrenal hyperplasia has been developed, allowing the false-positive rate associated with screening for 17-hydroxyprogesterone by immunoassay to be determined.

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

Science.gov (United States)

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

2015-10-01

A method, using liquid chromatography with tandem mass spectrometric detection (LC-MS/MS), was developed for the determination of suvorexant (MK-4305, Belsomra(®)), a selective dual orexin receptor antagonist for the treatment insomnia, in human plasma over the concentration range of 1-1000ng/mL. Stable isotope labeled (13)C(2)H3-suvorexant was used as an internal standard. The sample preparation procedure utilized liquid-liquid extraction, in the 96-well format, of a 100μL plasma sample with methyl t-butyl ether. The compounds were chromatographed under isocratic conditions on a Waters dC18 (50×2.1mm, 3μm) column with a mobile phase consisting of 30/70 (v/v %) 10mM ammonium formate, pH3/acetonitrile at a flow rate of 0.3mL/min. Multiple reaction monitoring of the precursor-to-product ion pairs for suvorexant (m/z 451→186) and (13)C(2)H3-suvorexant (m/z 455→190) on an Applied Biosystems API 4000 tandem mass spectrometer was used for quantitation. Intraday assay precision, assessed in six different lots of control plasma, was within 10% CV at all concentrations, while assay accuracy ranged from 95.6 to 105.0% of nominal. Quality control (QC) samples in plasma were stored at -20°C. Initial within day analysis of QCs after one freeze-thaw cycle showed accuracy within 9.5% of nominal with precision (CV) of 6.7% or less. The plasma QC samples were demonstrated to be stable for up to 25 months at -20°C. The method described has been used to support clinical studies during Phase I through III of clinical development. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultra Performance Liquid Chromatography Tandem Mass ...

African Journals Online (AJOL)

NICOLAAS

drugs alone.16. After a single oral dose of 120–800 mg of NTB in healthy sub- jects in a fasting state the peak plasma NTB concentration (tmax) was found to be 4–7 h, with a half-life of approximately 9–17 h.17 ... performance liquid chromatography mass spectrometry/mass .... to the likely biological plasma constituents.

High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry in the positive and negative ionization modes.

Science.gov (United States)

Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masae; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Seno, Hiroshi

2011-06-01

In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in the positive and negative ionization modes using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with Acquity UPLC BEH C(18) column and Acquity TQD tandem quadrupole mass spectrometer equipped with an electrospray ionization interface. The calibration curves for muscle relaxants spiked into human plasma equally showed good linearities in the nanogram per milliliter order range. The detection limits (signal-to-noise ratio = 3) was as low as 0.1-2 ng/mL. The method gave satisfactory recovery rates, accuracy, and precision for quality control samples spiked with muscle relaxants. To further validate the present method, 250 mg of chlorphenesin carbamate was orally administered to a healthy male volunteer, and the concentrations of chlorphenesin carbamate in plasma were measured 0.5, 1, 2, 4, 6, and 8 h after dosing; their concentrations in human plasma were between 0.62 and 2.44 μg/mL. To our knowledge, this is the first report describing simultaneous analysis of over more than two central-acting muscle relaxants by liquid chromatography-tandem mass spectrometry. This has been realized by the capability of our instrument for simultaneous multiple reaction monitoring of the target compounds in both positive and negative ionization modes. Therefore, the present method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

Population and particle decay of isobaric analog states in medium heavy nuclei

International Nuclear Information System (INIS)

Gales, S.

1980-05-01

The systematic features of proton stripping and neutron pick-up reactions to Isobaric Analog States in medium heavy nuclei are presented. The ( 3 He,d) reaction investigated at high incident energy is shown to selectively excite high-spin particle-analog states. Similarly the ( 3 He,α) reaction populates hole-analog states. The recent results related to such highly excited states in a wide range of nuclei ( 48 Ca to 208 Pb) are discussed in the framework of the DWBA theory of direct reactions with special emphasis on the treatment of unbound proton states or deeply-bound neutron hole states. The particle decay of Isobaric Analog States are investigated using the ( 3 He,d p) and ( 3 He, α p) sequential processes. The experimental method developed at Orsay (0 0 detection) for particle-particle angular correlations is presented. The advantage and the limits of such approach are illustrated by typical examples of particle decays: core-excited states, neutron particle-hole multiplets and the first observation of the proton emission of hole-analog levels. In conclusion new experimental approaches such as asymmetry measurements for analog states observed in transfer reactions or possible population of double analog states in heavy nuclei are discussed

The determination of long life radionuclides by means of sector field ICP mass spectrometry

International Nuclear Information System (INIS)

Kerl, W.; Becker, J.S.; Dietze, H.J.; Dannecker, W.

1996-01-01

Different analytical processes for determining long life radionuclides by means of double-focussing sector field ICP mass spectrometry are described. In determining long life radionuclides by means of ICP-MS, on the one hand the analytical problem areas are in the interference of isobaric atom or molecule ions (eg: 151 Eu + - 151 Sm + , 79 Se + - 39 Ar 40 ArH + ) and on the other hand in the high detection limits when using commercial sample introduction systems (eg: For 129 I). An online coupling of HPLC and ICP-MS was built up for the separation of isobaric atom ions and was tested for the separation of isobaric atom ions and was tested for its efficiency in the separation of lanthanides. Special sample introduction systems for ICP-MS were developed for the analysis of 129 I, by which the sensitivity of detection can be appreciably improved compared to commercial sample introduction systems. (orig.) [de

Kinetic study for a stress testing of L,L-ethylenedicysteine by ultra-performance liquid chromatography/tandem mass spectrometry analysis

Energy Technology Data Exchange (ETDEWEB)

Sun Xiaotao [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Qiao Jinping, E-mail: Qiaojp920@gmail.co [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Zhu Lin; Qiao Hongwen [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Zhong Jianguo [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China)

2010-12-15

This study proposed a stress testing to study oxidative stability and estimate the potential shelf-life of L,L-ethylenedicysteine (L,L-EC) under normal storage temperature condition (20-25 {sup o}C). L,L-EC was detected as a function of time at four different temperatures by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). The degradation of L,L-EC followed the first order kinetics, and the temperature-dependent kinetics was well described by the linear Arrhenius equation. The activation energy (E{sub a}) was calculated, and the shelf-life at 25 and 4 {sup o}C was predicted. The results are useful for the proper storage and quality evaluation of L,L-EC.

Kinetic study for a stress testing of L,L-ethylenedicysteine by ultra-performance liquid chromatography/tandem mass spectrometry analysis

International Nuclear Information System (INIS)

Sun Xiaotao; Qiao Jinping; Zhu Lin; Qiao Hongwen; Zhong Jianguo

2010-01-01

This study proposed a stress testing to study oxidative stability and estimate the potential shelf-life of L,L-ethylenedicysteine (L,L-EC) under normal storage temperature condition (20-25 o C). L,L-EC was detected as a function of time at four different temperatures by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). The degradation of L,L-EC followed the first order kinetics, and the temperature-dependent kinetics was well described by the linear Arrhenius equation. The activation energy (E a ) was calculated, and the shelf-life at 25 and 4 o C was predicted. The results are useful for the proper storage and quality evaluation of L,L-EC.

Fragmentation analysis of water-soluble atmospheric organic matter using ultrahigh-resolution FT-ICR mass spectrometry.

Science.gov (United States)

Leclair, Jeffrey P; Collett, Jeffrey L; Mazzoleni, Lynn R

2012-04-17

Isolated water-soluble atmospheric organic matter (AOM) analytes extracted from radiation fogwater samples were analyzed using collision induced dissociation with ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Tandem mass analysis was performed on several mass ranges between 100 and 400 Da to characterize the functional groups of AOM species. Compounds containing nitrogen and/or sulfur were targeted because of the high number of oxygen atoms contained in their molecular formulas. Due to the large number of isobaric ions in the precursor isolation ranges, large numbers of product ions resulted from collision induced dissociation. Common neutral losses were assigned by matching the molecular formulas of the expected product ions with the detected product ions within the appropriate mass spectra. Since polar functional groups are expected to affect the hygroscopic properties of aerosols, the losses of H(2)O, CO(2), CH(3)OH, HNO(3), CH(3)NO(3), SO(3), SO(4) and combinations of these were specifically targeted. Among the 421 compounds studied, the most frequently observed neutral losses were CO(2) (54%), H(2)O (43%) and CH(3)OH (40%). HNO(3) losses were observed for 63% of the studied nitrogen containing compounds and 33% of the studied compounds containing both nitrogen and sulfur. SO(3) losses were observed for 85% of the studied sulfur containing compounds and 42% of studied compounds containing both nitrogen and sulfur. A number of molecular formulas matching those of monoterpene ozonolysis SOA were observed; they include organonitrates, organosulfates, and nitroxy-organosulfates. Overall, the results of fragmentation analysis of 400+ individual molecular precursors elucidate the complexity and multifunctional nature of the isolated water-soluble AOM.

Multi-detection of preservatives in cheeses by liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Fuselli, Fabio; Guarino, Chiara; La Mantia, Alessandro; Longo, Lucia; Faberi, Angelo; Marianella, Rosa Maria

2012-10-01

The incorrect use of preservatives in cheeses may compromise food safety and damage consumers. According to the law, more than one preservative may be contemporarily used in cheeses. So a method for their contemporary detection may be useful for both manufacturers and control agencies quality control. In this research a liquid chromatography-tandem mass spectrometric with electrospray ionization method for the multi-determination of seven preservatives (benzoic acid, citric acid, hexamethylenetetramine, lysozyme, natamycin, nisin and sorbic acid) in cheese was developed. The preservatives were contemporarily extracted from cheese by a single procedure, and analyzed by RP-LC/ESI-MS/MS (Ion Trap) in positive ionization mode, with single reaction monitoring (SRM) acquisition. Three sample types (hard, pasta filata and fresh cheese) were used for method evaluation. Recoveries were mostly higher than 90%; MDLs ranged from 0.02 to 0.26 mgkg(-1), and MQLs were included between 0.07 and 0.88 mgkg(-1). Due to matrix effect, quantitation was performed by referring to a matrix matched calibration curve, for each cheese typology. This method was also applied to commercial cheese samples, with good results. It appears fast, reliable and suitable for both screening and confirmation of the presence and quantitation of the preservatives in a single, multi-detection analysis. Copyright © 2012 Elsevier B.V. All rights reserved.

Role of Mass Spectrometry in Clinical Endocrinology.

Science.gov (United States)

Ketha, Siva S; Singh, Ravinder J; Ketha, Hemamalini

2017-09-01

The advent of mass spectrometry into the clinical laboratory has led to an improvement in clinical management of several endocrine diseases. Liquid chromatography tandem mass spectrometry found some of its first clinical applications in the diagnosis of inborn errors of metabolism, in quantitative steroid analysis, and in drug analysis laboratories. Mass spectrometry assays offer analytical sensitivity and specificity that is superior to immunoassays for many analytes. This article highlights several areas of clinical endocrinology that have witnessed the use of liquid chromatography tandem mass spectrometry to improve clinical outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

Estimation of the radiation strength, dose equivalent and mean gamma-ray energy form p+ sup 2 sup 3 sup 8 U fission products

CERN Document Server

Kawakami, H

2003-01-01

On 100 isobars from 72 to 171 mass number, the radiation strength, dose equivalent and mean gamma-ray energy from p+ sup 2 sup 3 sup 8 U fission products at Tandem accelerator facility were estimated on the basis of data of proton induced fission mass yield by T. Tsukada. In order to control radiation, the decay curves of radiation of each mass after irradiation were estimated and illustrated. These calculation results showed 1) the peak of p+ sup 2 sup 3 sup 8 U fission products is 101 and 133 mass number. 2) gamma-ray strength of target ion source immediately after irradiation is 3.12x10 sup 1 sup 1 (Radiation/s) when it repeated 4 cycles of UC sub 2 (2.6 g/cm sup 2) target radiated by 30 MeV and 3 mu A proton for 5 days and then cooled for 2 days. It decreased to 3.85x10 sup 1 sup 0 and 6.7x10 sup 9 (Radiation/s) after one day and two weeks cooling, respectively. 3) Total dose equivalent is 3.8x10 sup 4 (mu S/h) at 1 m distance without shield. 4) There are no problems on control the following isobars, beca...

On-line immunoaffinity column-liquid chromatography-tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample.

Science.gov (United States)

Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

2006-11-10

An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

Fragmentation study of iridoid glucosides through positive and negative electrospray ionization, collision-induced dissociation and tandem mass spectrometry.

Science.gov (United States)

Es-Safi, Nour-Eddine; Kerhoas, Lucien; Ducrot, Paul-Henri

2007-01-01

Mass spectrometric methodology based on the combined use of positive and negative electrospray ionization, collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS) has been applied to the mass spectral study of a series of six naturally occurring iridoids through in-source fragmentation of the protonated [M+H]+, deprotonated [M--H]- and sodiated [M+Na]+ ions. This led to the unambiguous determination of the molecular masses of the studied compounds and allowed CID spectra of the molecular ions to be obtained. Valuable structural information regarding the nature of both the glycoside and the aglycone moiety was thus obtained. Glycosidic cleavage and ring cleavages of both aglycone and sugar moieties were the major fragmentation pathways observed during CID, where the losses of small molecules, the cinnamoyl and the cinnamate parts were also observed. The formation of the ionized aglycones, sugars and their product ions was thus obtained giving information on their basic skeleton. The protonated, i.e. [M+H]+ and deprotonated [M--H]-, ions were found to fragment mainly by glycosidic cleavages. MS/MS spectra of the [M+Na]+ ions gave complementary information for the structural characterization of the studied compounds. Unlike the dissociation of protonated molecular ions, that of sodiated molecules also provided sodiated sugar fragments where the C0+ fragment corresponding to the glucose ion was obtained as base peak for all the studied compounds. Copyright (c) 2007 John Wiley & Sons, Ltd.

Technical note: development and validation of a method using ultra performance liquid chromatography coupled with tandem mass spectrometry for determination of vitamin B12 concentrations in milk and dairy products.

Science.gov (United States)

Zironi, E; Gazzotti, T; Barbarossa, A; Devicienti, C; Scardilli, M; Pagliuca, G

2013-05-01

A method using ultra performance liquid chromatography coupled with tandem mass spectrometry was developed to measure cobalamins in naturally enriched raw milk and to evaluate their fate during thermal treatments and along the process of cheese making. After addition of methotrexate as internal standard, samples were submitted to heat treatment in the presence of cyanide, which converts all the less-stable cobalamins into cyanocobalamin; then, purification was performed by a solid-phase extraction step. Reverse-phase ultra performance liquid chromatography separation coupled with tandem mass spectrometry provided a fast and reliable determination. Mass spectrometric analysis was carried out in multiple reaction monitoring mode. The monitored transitions were m/z 678.36 → 147.10 and 678.36 → 359.30 for vitamin B12 and m/z 455.22 → 175.13 and 455.22 → 308.22 for methotrexate (internal standard). The limit of quantification was 2 ng/g. The method showed good linearity from 2 to 20 ng/g (R(2) ≥ 0.98) and intra- and interday precisions were always less than 19%. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Real-time hydrogen/deuterium exchange kinetics via supercharged electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Sterling, Harry J; Williams, Evan R

2010-11-01

Amide hydrogen/deuterium exchange (HDX) rate constants of bovine ubiquitin in an ammonium acetate solution containing 1% of the electrospray ionization (ESI) "supercharging" reagent m-nitrobenzyl alcohol (m-NBA) were obtained using top-down, electron transfer dissociation (ETD) tandem mass spectrometry (MS). The supercharging reagent replaces the acid and temperature "quench" step in the conventional MS approach to HDX experiments by causing rapid protein denaturation to occur in the ESI droplet. The higher charge state ions that are produced with m-NBA are more unfolded, as measured by ion mobility, and result in higher fragmentation efficiency and higher sequence coverage with ETD. Single amino acid resolution was obtained for 44 of 72 exchangeable amide sites, and summed kinetic data were obtained for regions of the protein where adjacent fragment ions were not observed, resulting in an overall spatial resolution of 1.3 residues. Comparison of these results with previous values from NMR indicates that the supercharging reagent does not cause significant structural changes to the protein in the initial ESI solution and that scrambling or back-exchange is minimal. This new method for top-down HDX-MS enables real-time kinetic data measurements under physiological conditions, similar to those obtained using NMR, with comparable spatial resolution and significantly better sensitivity.

Middle-down hybrid chromatography/tandem mass spectrometry workflow for characterization of combinatorial post-translational modifications in histones.

Science.gov (United States)

Sidoli, Simone; Schwämmle, Veit; Ruminowicz, Chrystian; Hansen, Thomas A; Wu, Xudong; Helin, Kristian; Jensen, Ole N

2014-10-01

We present an integrated middle-down proteomics platform for sensitive mapping and quantification of coexisting PTMs in large polypeptides (5-7 kDa). We combined an RP trap column with subsequent weak cation exchange-hydrophilic interaction LC interfaced directly to high mass accuracy ESI MS/MS using electron transfer dissociation. This enabled automated and efficient separation and sequencing of hypermodified histone N-terminal tails for unambiguous localization of combinatorial PTMs. We present Histone Coder and IsoScale software to extract, filter, and analyze MS/MS data, including quantification of cofragmenting isobaric polypeptide species. We characterized histone tails derived from murine embryonic stem cells knockout in suppressor of zeste12 (Suz12(-/-) ) and quantified 256 combinatorial histone marks in histones H3, H4, and H2A. Furthermore, a total of 713 different combinatorial histone marks were identified in purified histone H3. We measured a seven-fold reduction of H3K27me2/me3 (where me2 and me3 are dimethylation and trimethylation, respectively) in Suz12(-) (/) (-) cells and detected significant changes of the relative abundance of 16 other single PTMs of histone H3 and other combinatorial marks. We conclude that the inactivation of Suz12 is associated with changes in the abundance of not only H3K27 methylation but also multiple other PTMs in histone H3 tails. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Large tandem accelerators

International Nuclear Information System (INIS)

Jones, C.M.

1976-01-01

The increasing importance of energetic heavy ion beams in the study of atomic physics, nuclear physics, and materials science has partially or wholly motivated the construction of a new generation of tandem accelerators designed to operate at maximum terminal potentials in the range 14 to 30 MV. In addition, a number of older tandem accelerators are now being significantly upgraded to improve their heavy ion performance. Both of these developments have reemphasized the importance of negative heavy ion sources. The new large tandem accelerators are described, and the requirements placed on negative heavy ion source technology by these and other tandem accelerators used for the acceleration of heavy ions are discussed. First, a brief description is given of the large tandem accelerators which have been completed recently, are under construction, or are funded for construction, second, the motivation for construction of these accelerators is discussed, and last, criteria for negative ion sources for use with these accelerators are presented

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

Directory of Open Access Journals (Sweden)

Praveen Srivastava

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

Online liquid chromatography-tandem mass spectrometry cyanide determination in blood.

Science.gov (United States)

Lacroix, C; Saussereau, E; Boulanger, F; Goullé, J P

2011-04-01

An original liquid chromatography-tandem mass spectrometry (LC-MS-MS) method coupled to online extraction has been developed for cyanide determination in blood. A method involving fluorimetric detection after naphthalene-2,3-dicarboxyaldehyde (NDA) complexation by taurine in the presence of cyanide was previously described. Its performance was limited because of the absence of an internal standard (IS). Using cyanide isotope (13)C(15)N as IS allowed quantification in MS-MS. After the addition of (13)C(15)N, 25 μL of blood were diluted in water and deproteinized with methanol. Following derivatization with NDA and taurine for 10 min at 4°C, 100 μL was injected into the online LC-MS-MS system. An Oasis HLB was used as an extraction column, and a C18 Atlantis was the analytical column. The chromatographic cycle was performed with an ammonium formate (20 mM, pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 6 min. Detection was performed in negative electrospray ionization mode (ESI(-)) with a Quattro Micro. For quantification, transitions of derivatives formed with CN and (13)C(15)N were monitored, respectively, as follows: 299.3/191.3 and 301.3/193.3. The procedure was fully validated, linear from 26 to 2600 ng/mL with limit of detection of 10 ng/mL. This method, using a small blood sample, is not only simple, but also time saving. The specificity and sensitivity of LC-MS-MS coupled to online extraction and using (13)C(15)N as the IS make this method very suitable for cyanide determination in blood and could be useful in forensic toxicology.

Quantification of Hydroxychloroquine in Blood Using Turbulent Flow Liquid Chromatography-Tandem Mass Spectrometry (TFLC-MS/MS).

Science.gov (United States)

Chambliss, Allison B; Füzéry, Anna K; Clarke, William A

2016-01-01

Hydroxychloroquine (HQ) is used routinely in the treatment of autoimmune disorders such as rheumatoid arthritis and lupus erythematosus. Issues such as marked pharmacokinetic variability and patient non-compliance make therapeutic drug monitoring of HQ a useful tool for management of patients taking this drug. Quantitative measurements of HQ may aid in identifying poor efficacy as well as provide reliable information to distinguish patient non-compliance from refractory disease. We describe a rapid 7-min assay for the accurate and precise measurement of HQ concentrations in 100 μL samples of human blood using turbulent flow liquid chromatography coupled to tandem mass spectrometry. HQ is isolated from EDTA whole blood after a simple extraction with its deuterated analog, hydroxychloroquine-d4, in 0.33 M perchloric acid. Samples are then centrifuged and injected onto the TFLC-MS/MS system. Quantification is performed using a nine-point calibration curve that is linear over a wide range (15.7-4000 ng/mL) with precisions of <5 %.

Simultaneous determination of β-agonists and monitoring in bovine tissues by liquid chromatography-tandem mass spectrometry

Directory of Open Access Journals (Sweden)

Kyunghun Jeong

2018-01-01

Full Text Available The misuse of β-agonists leads to a potential risk to public health and is forbidden in many countries. We developed a rapid, sensitive and reliable multi-residue detection method for zilpaterol, ractopamine, and clenbuterol in bovine tissues by liquid chromatography–tandem mass spectrometry. Residues were extracted in ethyl acetate after protein precipitation, and then analyzed by the developed method. Good linearities (R2 > 0.99 were observed, and the recoveries of zilpaterol, ractopamine, and clenbuterol were 99%, 74%, and 102%, respectively. The limits of quantitation for zilpaterol, ractopamine, and clenbuterol were 1.3, 5.0, and 1.7 ng/g, respectively. The method is also applied successfully to bovine tissues within the Korean National Residue Programme. None of the 3 β-agonists were detected from 50 domestic samples. However, zilpaterol (6.3 ng/g was quantified in one out of the 50 imported samples. The application of this method will be helpful in quality control analysis of β-agonists residues in bovine tissues.

Rapid determination of vitamin D₃ in milk-based infant formulas by liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Kwak, Byung-Man; Jeong, In-Seek; Lee, Moon-Seok; Ahn, Jang-Hyuk; Park, Jong-Su

2014-12-15

A rapid and simple sample preparation method for vitamin D3 (cholecalciferol) was developed for emulsified dairy products such as milk-based infant formulas. A sample was mixed in a 50 mL centrifuge tube with the same amount of water and isopropyl alcohol to achieve chemical extraction. Ammonium sulfate was used to induce phase separation. No-heating saponification was performed in the sample tube by adding KOH, NaCl, and NH3. Vitamin D3 was then separated and quantified using liquid chromatography-tandem mass spectrometry. The results for added recovery tests were in the range 93.11-110.65%, with relative standard deviations between 2.66% and 2.93%. The results, compared to those obtained using a certified reference material (SRM 1849a), were within the range of the certificated values. This method could be implemented in many laboratories that require time and labour saving. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multiclass method for the quantification of 92 veterinary antimicrobial drugs in livestock excreta, wastewater, and surface water by liquid chromatography with tandem mass spectrometry.

Science.gov (United States)

Gao, Jinfang; Cui, Yonghui; Tao, Yanfei; Huang, Lingli; Peng, Dapeng; Xie, Shuyu; Wang, Xu; Liu, Zhenli; Chen, Dongmei; Yuan, Zonghui

2016-11-01

A simple multiresidue method was developed for detecting and quantifying 92 veterinary antimicrobial drugs from eight classes (β-lactams, quinolones, sulfonamides, tetracyclines, lincomycins, macrolides, chloramphenicols, and pleuromutilin) in livestock excreta and water by liquid chromatography with tandem mass spectrometry. The feces samples were extracted by ultrasound-assisted extraction with a mixture of acetonitrile/water (80:20, v/v) and edetate disodium, followed by a cleanup using solid-phase extraction with an amino cartridge. Water samples were purified with hydrophilic-lipophilic balance solid-phase extraction column. Urine samples were extracted with acetonitrile and edetate disodium. Detection of veterinary antimicrobial drugs was achieved by liquid chromatography with tandem mass spectrometry using both positive and negative electrospray ionization mode. The recovery values of veterinary antimicrobial drugs in feces, urine, and water samples were 75-99, 85-110, and 85-101% and associated relative standard deviations were less than 15, 10, and 8%, respectively. The limits of quantification in feces, urine, and water samples were 0.5-1, 0.5-1, and 0.01-0.05 μg/L, respectively. This method was applied to determine real samples obtained from local farms and provides reliable quantification and identification results of 92 veterinary antimicrobial drugs in livestock excreta and water. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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...

Multiclass analysis of antibiotic residues in honey by ultraperformance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Vidal, Jose Luis Martínez; Aguilera-Luiz, María Del Mar; Romero-González, Roberto; Frenich, Antonia Garrido

2009-03-11

A method has been developed and validated for the simultaneous analysis of different veterinary drug residues (macrolides, tetracyclines, quinolones, and sulfonamides) in honey. Honey samples were dissolved with Na(2)EDTA, and veterinary residues were extracted from the supernatant by solid-phase extraction (SPE), using OASIS HLB cartridges. The separation and determination was carried out by ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), using an electrospay ionization source (ESI) in positive mode. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring (MRM) of two ion transitions per compound to provide a high degree of sensitivity and specificity. The method was validated, and mean recoveries were evaluated at three concentration levels (10, 50, and 100 microg/kg), ranging from 70 to 120% except for doxycycline, erythromycin, and tylmicosin with recovery higher than 50% at the three levels assayed. Relative standard deviations (RSDs) of the recoveries were less than 20% within the intraday precision and less than 25% within the interday precision. The limits of quantification (LOQs) were always lower than 4 microg/kg. The developed procedure was applied to 16 honey samples, and erythromycin, sarafloxacin, and tylosin were found in a few samples.

Determination of flomoxef in human plasma by liquid chromatography/electrospray ionization tandem mass spectrometry.

Science.gov (United States)

Kravtsova, Oxana Yu; Paramonov, Sergey A; Vasilevich, Natalya I; Kazyulkin, Denis N; Vlasova, Ekaterina; Engsig, Michael

2013-12-01

A specific, sensitive, rapid and reproducible method for the determination of flomoxef in human plasma using high-performance liquid chromatography-tandem mass spectrometry was developed and validated. Flomoxef was detected using an electrospay ionization method operated in negative-ion mode. Chromatographic separation was performed in gradient elution mode on a Luna® C18(2) column (3 μM, 20 × 4.0 mm) at a flow rate of 1 mL/min and runtime 3.5 min. The mobile phase consisted of acetonitrile and water containing 0.1% formic acid as additive. Extraction of flomoxef from plasma and precipitation of plasma proteins was performed with acetonitrile with an absolute recovery of 86.4 ± 1.6%. The calibration curve was linear with a correlation coefficient of 0.999 over the concentration range 10-5000 ng/mL and the lower limit of quantification was 10 ng/mL. The intra- and inter-day precisions were flomoxef revealed that it could be successfully analyzed at 4 ºС over 24 h, but it was unstable in solutions at room temperature during short-term storage (4 h) and several freeze-thaw cycles. Copyright © 2013 John Wiley & Sons, Ltd.

Proteomic analysis of Taenia ovis metacestodes by high performance liquid chromatography-coupled tandem mass spectrometry.

Science.gov (United States)

Zheng, Yadong

2017-03-15

Taenia ovis metacestodes reside in the muscle of sheep and goats, and may cause great economic loss due to condemnation of carcasses if not effectively controlled. Although advances have been made in the control of T. ovis infection, our knowledge of T. ovis biology is limited. Herein the protein profiling of T. ovis metacestodes was determined by liquid chromatography-linked tandem mass spectrometry. A total of 966 proteins were identified and 25.1% (188/748) were annotated to be associated with metabolic pathways. Consistently, GO analysis returned a metabolic process (16.27%) as one of two main biological process terms. Moreover, it was found that 24 proteins, including very low-density lipoprotein receptor, enolase, paramyosin and endophilin B1, were abundant in T. ovis metacestodes. These proteins may be associated with motility, metabolism, signaling, stress, drug resistance and immune responses. Furthermore, comparative analysis of 5 cestodes revealed the presence of Taenia-specific enolases. These data provide clues for better understanding of T. ovis biology, which is informative for effective control of infection. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid to liquid extraction and liquid chromatography-tandem mass spectrometry determination of hainanmycin in feed.

Science.gov (United States)

Wang, Ze Ping; Shen, Jian Zhong; Linhardt, Robert J; Jiang, Hui; Cheng, Lin Li

2017-03-01

Hainanmycin is a new veterinary polyether antibiotic and has few sensitive analytical method in present days. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) relying on multiple reaction monitoring (MRM) detection was developed for analysis of hainanmycin in animal feed. Feed samples were extracted with ethyl acetate and purified by two steps of liquid-liquid extraction (LLE) to get rid of water solvable matrix and lipids one by one. The final simple was analyzed by LC-MS/MS. The LC mobile phase was composed of 0.1% aqueous formic acid and 0.1% formic acidified acetonitrile by gradient elution. Average recoveries ranged from 74.22% to 87.85%, as determined by spiking with 2.0 (LOQ) ∼2500μgkg -1 of hainanmycin. The inter-day and intra-day coefficient of variation was 9.21% to 11.77% and 7.67% to 13.49%, respectively. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.36μgkg -1 and 2.0μgkg -1 , respectively. Copyright © 2016. Published by Elsevier B.V.

Determination of Grayanotoxins from Rhododendron brachycarpum in Dietary Supplements and Homemade Wine by Liquid Chromatography-Quadrupole Time-of-Flight-Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry.

Science.gov (United States)

Hwang, Taeik; Noh, Eunyoung; Jeong, Ji Hye; Park, Sung-Kwan; Shin, Dongwoo; Kang, Hoil

2018-02-28

A sensitive and specific high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of grayanotoxins I and III in dietary supplements and homemade wine. Grayanotoxins I and III were successfully extracted using solid-phase extraction cartridges, characterized by LC-QTOF-MS, and quantitated by LC-MS/MS. The LC-MS/MS calibration curves were linear over concentrations of 10-100 ng/mL (grayanotoxin I) and 20-400 ng/mL (grayanotoxin III). Grayanotoxins I and III were found in 51 foodstuffs, with quantitative determinations revealing total toxin concentrations of 18.4-101 000 ng/mL (grayanotoxin I) and 15.3-56 000 ng/mL (grayanotoxin III). The potential of the validated method was demonstrated by successful quantitative analysis of grayanotoxins I and III in dietary supplements and homemade wine; the method appears suitable for the routine detection of grayanotoxins I and III from Rhododendron brachycarpum.

Particle-hole calculation of the isobaric analog and isovector monopole resonances

International Nuclear Information System (INIS)

Auerbach, N.; Nguyen Van Giai

1977-06-01

The correlated proton particle-neutron hole spectrum is calculated for N>Z nuclei using a Skyrme type interaction and the response function method. The basis of the calculation is a complete one particle-one hole space with the continuum included. As a result the distribution of the isovector monopole strength in the analog nucleus is obtained. This distribution has a narrow peak which corresponds to the isobaric analog resonance and at higher energies a broad peak which is the isovector monopole resonance. The coupling between these two states is inherent in the calculation

Single-task and dual-task tandem gait test performance after concussion.

Science.gov (United States)

Howell, David R; Osternig, Louis R; Chou, Li-Shan

2017-07-01

To compare single-task and dual-task tandem gait test performance between athletes after concussion with controls on observer-timed, spatio-temporal, and center-of-mass (COM) balance control measurements. Ten participants (19.0±5.5years) were prospectively identified and completed a tandem gait test protocol within 72h of concussion and again 1 week, 2 weeks, 1 month, and 2 months post-injury. Seven uninjured controls (20.0±4.5years) completed the same protocol in similar time increments. Tandem gait test trials were performed with (dual-task) and without (single-task) concurrently performing a cognitive test as whole-body motion analysis was performed. Outcome variables included test completion time, average tandem gait velocity, cadence, and whole-body COM frontal plane displacement. Concussion participants took significantly longer to complete the dual-task tandem gait test than controls throughout the first 2 weeks post-injury (mean time=16.4 [95% CI: 13.4-19.4] vs. 10.1 [95% CI: 6.4-13.7] seconds; p=0.03). Single-task tandem gait times were significantly lower 72h post-injury (p=0.04). Dual-task cadence was significantly lower for concussion participants than controls (89.5 [95% CI: 68.6-110.4] vs. 127.0 [95% CI: 97.4-156.6] steps/minute; p=0.04). Moderately-high to high correlations between tandem gait test time and whole-body COM medial-lateral displacement were detected at each time point during dual-task gait (r s =0.70-0.93; p=0.03-0.001). Adding a cognitive task during the tandem gait test resulted in longer detectable deficits post-concussion compared to the traditional single-task tandem gait test. As a clinical tool to assess dynamic motor function, tandem gait may assist with return to sport decisions after concussion. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Quantification of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate using stable isotope dilution liquid chromatography with atmospheric-pressure photoionization tandem mass spectrometry.

Science.gov (United States)

Zhang, Xiaotao; Hou, Hongwei; Chen, Huan; Liu, Yong; Wang, An; Hu, Qingyuan

2015-09-17

A stable isotope dilution liquid chromatography with tandem mass spectrometry method for the analysis of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate was developed and validated. Compared with previously reported methods, this method has lower limits of detection (0.04-1.35 ng/cig). Additionally, the proposed method saves time, reduces the number of separation steps, and reduces the quantity of solvent needed. The new method was applied to evaluate polycyclic aromatic hydrocarbon content in 213 commercially available cigarettes in China, under the International Standardization Organization smoking regime and the Health Canadian intense smoking regime. The results showed that the total polycyclic aromatic hydrocarbon content was more than two times higher in samples from the Health Canadian intense smoking regime than in samples from the International Standardization Organization smoking regime (1189.23 vs. 2859.50 ng/cig, ppolycyclic aromatic hydrocarbons (and total polycyclic aromatic hydrocarbons) increased with labeled tar content in both of the tested smoking regimes. There was a positive correlation between total polycyclic aromatic hydrocarbons under the International Standardization Organization smoking regime with that under the Health Canadian intense smoking regime. The proposed liquid chromatography with tandem mass spectrometry method is satisfactory for the rapid, sensitive, and accurately quantitative evaluation of polycyclic aromatic hydrocarbon content in cigarette smoke condensate, and it can be applied to assess potential health risks from smoking. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Ultrapressure liquid chromatography-tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for quantification of 4-methoxydiphenylmethane in pharmacokinetic evaluation.

Science.gov (United States)

Farhan, Nashid; Fitzpatrick, Sean; Shim, Yun M; Paige, Mikell; Chow, Diana Shu-Lian

2016-09-05

4-Methoxydiphenylmethane (4-MDM), a selective augmenter of Leukotriene A4 Hydrolase (LTA4H), is a new anti-inflammatory compound for potential treatment of chronic obstructive pulmonary disease (COPD). Currently, there is no liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the quantification of 4-MDM. A major barrier for developing the LC-MS/MS method is the inability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) to ionize 4-MDM due to its hydrophobicity and lack of any functional group for ionization. With the advent of atmospheric pressure photoionization (APPI) technique, many hydrophobic compounds have been demonstrated to ionize by charge transfer reactions. In this study, a highly sensitive ultrapressure liquid chromatography tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for the quantifications of 4-MDM in rat plasma has been developed and validated. 4-MDM was extracted from the plasma by solid phase extraction (SPE) and separated chromatographically using a reverse phase C8 column. The photoionization (PI) was achieved by introducing anisole as a dopant to promote the reaction of charge transfer. The assay with a linear range of 5 (LLOQ)-400ngmL(-1) met the regulatory requirements for accuracy, precision and stability. The validated assay was employed to quantify the plasma concentrations of 4-MDM after an oral dosing in Sprague Dawley (SD) rats. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry.

Science.gov (United States)

Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

2018-01-01

At present, approximately 17-25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration-liquid chromatography-electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro . The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF-LC-ESI-MS/MS): ultrafiltration-liquid chromatography-electrospray ionization tandem mass spectrometry; (ACh

Rapid Screening and Characterization of Acetylcholinesterase Inhibitors from Yinhuang Oral Liquid Using Ultrafiltration-liquid Chromatography-electrospray Ionization Tandem Mass Spectrometry

Science.gov (United States)

Zhang, Haomin; Guo, Yinan; Meng, Lingwen; Sun, Hui; Yang, Yinping; Gao, Ying; Sun, Jiaming

2018-01-01

Background: At present, approximately 17–25 million people in the world suffer from Alzheimer's disease (AD). The most efficacious and acceptable therapeutic drug clinically are the acetylcholinesterase inhibitors (AChEIs). Yinhuang oral liquid is a Chinese medicine preparation which contains AChEIs according to the literatures. However, no strategy has been presented for rapid screening and identification of AChEIs from Yinhuang oral liquid. Objective: To develop a method for rapid screening and identification of AChEIs from Yinhuang oral liquid using ultrafiltration–liquid chromatography–electrospray ionization tandem mass spectrometry (UF-LC-ESI-MS/MS). Materials and Methods: In this study, UF incubation conditions such as enzyme concentration, incubation time, and incubation temperature were optimized so as to get better screening results. The AChEIs from Yinhuang oral liquid were identified by high-performance liquid chromatography-ESI-MS and the improved Ellman method was used for the AChE inhibitory activity test in vitro. Results: The results showed that Yinhuang oral liquid can inhibit the activity of AChE. We screened and identified seven compounds with potential AChE inhibitory activity from Yinhuang oral liquid, which provided experimental basis for the treatment and prevention of AD. Conclusion: The current technique was used to directly screen the active ingredients with acetylcholinesterase inhibition from complex traditional Chinese medicine, which was simple, rapid, accurate, and suitable for high-throughput screening of AChEI from complex systems. SUMMARY A UF-LC-ESI-MS/MS method for rapid screening and identification of AChEIs from Yinhuang oral liquid was developedSeven compounds were screened and identified with potential AChE inhibitory activity from Yinhuang oral liquidIt provided experimental basis of Yinhuang oral liquid for the treating and preventing AD. Abbreviations used: (AD): Alzheimer's disease; (UF

Determination of cyclovirobuxine D in human plasma by liquid chromatography tandem mass spectrometry and application in a pharmacokinetic study

Directory of Open Access Journals (Sweden)

Ling-li Mu

2011-10-01

Full Text Available A sensitive and reliable method based on liquid chromatography tandem mass spectrometry (LC–MS/MS for the quantitation of cyclovirobuxine D in human plasma has been developed and validated. Sample preparation by solid phase extraction was followed by separation on a CN column with a mobile phase of methanol–water (95:5, v/v containing 0.2% formic acid. Mass spectrometric detection in the positive ion mode was carried out by selected reaction monitoring (SRM of the transitions at m/z 403.0→372.0 for cyclovirobuxine D and m/z 325.0→234.0 for citalopram (internal standard. The method was linear in the range 10–200 ng/L with LLOQ of 10 ng/L, recovery >85%, and no significant matrix effects. Intra- and inter-day precisions were all <9% with accuracies of 94.0–104.8%. The method was successfully applied to a pharmacokinetic study involving a single oral administration of a 2 mg cyclovirobuxine D tablet to twenty-two healthy Chinese volunteers.

Optimisation of pressurized liquid extraction using a multivariate chemometric approach for the determination of anticancer drugs in sludge by ultra high performance liquid chromatography-tandem mass spectrometry

OpenAIRE

Seira , Jordan; Claparols , Catherine; Joannis-Cassan , Claire; Albasi , Claire; Montréjaud-Vignoles , Mireille; Sablayrolles , Caroline

2013-01-01

International audience; The present paper describes an analytical method for the determination of 2 widely administered anticancer drugs, ifosfamide and cyclophosphamide, contained in sewage sludge. The method relies on the extraction from the solid matrix by pressurized liquid extraction, sample purification by solid-phase extraction and analysis by ultra high performance liquid chromatography coupled with tandem mass spectrometry. The different parameters affecting the extraction efficiency...

Derivation of a thermodynamic closure relation in the isothermal-isobaric ensemble using quasi-Gaussian entropy theory

NARCIS (Netherlands)

Apol, M.E F; Amadei, A; Berendsen, H.J.C.

1996-01-01

In an analogous way as was done previously in the canonical ensemble, we derived for dilute gases an approximated thermodynamic closure relation in the isothermal-isobaric ensemble using quasi-Gaussian entropy theory. For the Gamma state, we formulated equations for the temperature dependence of

Determination of phosphatidylethanolamine molecular species in various food matrices by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS2).

Science.gov (United States)

Zhou, Li; Zhao, Minjie; Ennahar, Saïd; Bindler, Françoise; Marchioni, Eric

2012-04-01

A liquid chromatographic-electrospray ionization-tandem mass spectrometric (LC-ESI-MS(2)) method has been developed for determination of the molecular species of phosphatidylethanolamine (PE) in four food matrices (soy, egg yolk, ox liver, and krill oil). The extraction and purification method consisted of a pressurized liquid extraction procedure for total lipid (TL) extraction, purification of phospholipids (PLs) by adsorption on a silica gel column, and separation of PL classes by semi-preparative normal-phase HPLC. Separation and identification of PE molecular species were performed by reversed-phase HPLC coupled with electrospray ionization tandem mass spectrometry (ESI-MS(2)). Methanol containing 5 mmol L(-1) ammonium formate was used as the mobile phase. A variety of PE molecular species were detected in the four food matrices. (C16:0-C18:2)PE, (C18:2-C18:2)PE, and (C16:0-C18:1)PE were the major PE molecular species in soy. Egg yolk PE contained (C16:0-C18:1)PE, (C18:0-C18:1)PE, (C18:0-C18:2)PE, and (C16:0-C18:2)PE as the major molecular species. Ox liver PE was rich in the species (C18:0-C18:1)PE, (C18:0-C20:4)PE, and (C18:0-C18:2)PE. Finally, krill oil which was particularly rich in (C16:0(alkyl)-C22:6(acyl))plasmanylethanolamine (PakE), (C16:0-C22:6)PE, and (C16:0-C20:5)PE, seemed to be an interesting potential source for supplementation of food with eicosapentaenoic acid and docosahexaenoic acid.

Similarity of High-Resolution Tandem Mass Spectrometry Spectra of Structurally Related Micropollutants and Transformation Products

Science.gov (United States)

Schollée, Jennifer E.; Schymanski, Emma L.; Stravs, Michael A.; Gulde, Rebekka; Thomaidis, Nikolaos S.; Hollender, Juliane

2017-12-01

High-resolution tandem mass spectrometry (HRMS2) with electrospray ionization is frequently applied to study polar organic molecules such as micropollutants. Fragmentation provides structural information to confirm structures of known compounds or propose structures of unknown compounds. Similarity of HRMS2 spectra between structurally related compounds has been suggested to facilitate identification of unknown compounds. To test this hypothesis, the similarity of reference standard HRMS2 spectra was calculated for 243 pairs of micropollutants and their structurally related transformation products (TPs); for comparison, spectral similarity was also calculated for 219 pairs of unrelated compounds. Spectra were measured on Orbitrap and QTOF mass spectrometers and similarity was calculated with the dot product. The influence of different factors on spectral similarity [e.g., normalized collision energy (NCE), merging fragments from all NCEs, and shifting fragments by the mass difference of the pair] was considered. Spectral similarity increased at higher NCEs and highest similarity scores for related pairs were obtained with merged spectra including measured fragments and shifted fragments. Removal of the monoisotopic peak was critical to reduce false positives. Using a spectral similarity score threshold of 0.52, 40% of related pairs and 0% of unrelated pairs were above this value. Structural similarity was estimated with the Tanimoto coefficient and pairs with higher structural similarity generally had higher spectral similarity. Pairs where one or both compounds contained heteroatoms such as sulfur often resulted in dissimilar spectra. This work demonstrates that HRMS2 spectral similarity may indicate structural similarity and that spectral similarity can be used in the future to screen complex samples for related compounds such as micropollutants and TPs, assisting in the prioritization of non-target compounds. [Figure not available: see fulltext.

Mapping Isobaric Aging onto the Equilibrium Phase Diagram

DEFF Research Database (Denmark)

Niss, Kristine

2017-01-01

The linear volume relaxation and the nonlinear volume aging of a glass-forming liquid are measured, directly compared, and used to extract the out-of-equilibrium relaxation time. This opens a window to investigate how the relaxation time depends on temperature, structure, and volume in parts...... of phase space that are not accessed by the equilibrium liquid. It is found that the temperature dependence of relaxation time is non-Arrhenius even in the isostructural case—challenging the Adam-Gibbs entropy model. Based on the presented data and the idea that aging happens through quasiequilibrium...... states, we suggest a mapping of the out-of-equilibrium states during isobaric aging to the equilibrium phase diagram. This mapping implies the existence of isostructural lines in the equilibrium phase diagram. The relaxation time is found to depend on the bath temperature, density, and a just single...

Redefining the Breast Cancer Exosome Proteome by Tandem Mass Tag Quantitative Proteomics and Multivariate Cluster Analysis.

Science.gov (United States)

Clark, David J; Fondrie, William E; Liao, Zhongping; Hanson, Phyllis I; Fulton, Amy; Mao, Li; Yang, Austin J

2015-10-20

Exosomes are microvesicles of endocytic origin constitutively released by multiple cell types into the extracellular environment. With evidence that exosomes can be detected in the blood of patients with various malignancies, the development of a platform that uses exosomes as a diagnostic tool has been proposed. However, it has been difficult to truly define the exosome proteome due to the challenge of discerning contaminant proteins that may be identified via mass spectrometry using various exosome enrichment strategies. To better define the exosome proteome in breast cancer, we incorporated a combination of Tandem-Mass-Tag (TMT) quantitative proteomics approach and Support Vector Machine (SVM) cluster analysis of three conditioned media derived fractions corresponding to a 10 000g cellular debris pellet, a 100 000g crude exosome pellet, and an Optiprep enriched exosome pellet. The quantitative analysis identified 2 179 proteins in all three fractions, with known exosomal cargo proteins displaying at least a 2-fold enrichment in the exosome fraction based on the TMT protein ratios. Employing SVM cluster analysis allowed for the classification 251 proteins as "true" exosomal cargo proteins. This study provides a robust and vigorous framework for the future development of using exosomes as a potential multiprotein marker phenotyping tool that could be useful in breast cancer diagnosis and monitoring disease progression.

Determination of seven bisphenol analogues in reed and Callitrichaceae by ultra performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Lu, Libin; Yang, Yunjia; Zhang, Jing; Shao, Bing

2014-03-15

An analytical procedure was developed to simultaneously determine bisphenol S, bisphenol F, bisphenol B, bisphenol A, bisphenol AF, tetrachlorobisphenol A, and tetrabromobisphenol A in reed and Callitrichaceae. Homogenized samples were extracted with acetonitrile and purified using an ENVI™-Carb cartridge followed by an NH2 cartridge. The analytes were separated and quantified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The recoveries at three fortified levels in reed and Callitrichaceae were 57-108% and 68-106%, respectively, with relative standard deviations of no more than 15% (n=6). The method limits of quantification and detection for the seven bisphenol analogues were 0.005-0.500μg/kg and 0.002-0.150μg/kg, respectively. This method was used to analyze the seven compounds in ten reed and Callitrichaceae samples collected from Zhejiang, China. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantification of total hexose on dry blood spot by tandem mass spectrometry.

Science.gov (United States)

Gong, Zhenhua; Tian, Guoli; Huang, Qiwei; Wang, Yanmin; Ge, Qingwei

2012-12-01

Because hypoglycemia and hyperglycemia are harmful and not always associated with overt clinical signs, it is necessary to have methods available to screen for glucose levels to detect hypoglycemia and diabetes as early as possible. A new method for such screening and the clinical determination of blood total hexose on a dry blood spot (DBS) using tandem mass spectrometry (MS/MS) was developed. The serum glucose controls and blood were prepared as DBS and then extracted into a methanol solution containing isotope-labeled internal standards. The methanolic extraction was subjected to HPLC, followed by MS/MS in positive ion mode. Multiple-reaction monitoring of m/z 203.1→23 was used to detect hexose, and m/z 209.0→23 was used for 13C6-D-glucose. The recoveries of blood glucose by MS/MS were 90%-102% with an R(2) value of 0.999 after linear regression (pblood total hexose in neonates aged 3-7 days (6.41±1.46 mmol/L) was lower than that in neonates aged 8-30 days (6.66±1.38 mmol/L), and it was lower in neonates than in children aged 1-72 months (7.19±1.87 mmol/L). Quantification of total hexose on a dry blood spot by MS/MS is accurate, reliable and feasible for screening and clinical tests. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Functionalized graphene quantum dots loaded with free radicals combined with liquid chromatography and tandem mass spectrometry to screen radical scavenging natural antioxidants from Licorice and Scutellariae.

Science.gov (United States)

Wang, Guoying; Niu, XiuLi; Shi, Gaofeng; Chen, Xuefu; Yao, Ruixing; Chen, Fuwen

2014-12-01

A novel screening method was developed for the detection and identification of radical scavenging natural antioxidants based on a free radical reaction combined with liquid chromatography with tandem mass spectrometry. Functionalized graphene quantum dots were prepared for loading free radicals in the complex screening system. The detection was performed with and without a preliminary exposure of the samples to specific free radicals on the functionalized graphene quantum dots, which can facilitate charge transfer between free radicals and antioxidants. The difference in chromatographic peak areas was used to identify potential antioxidants. This is a novel approach to simultaneously evaluate the antioxidant power of a component versus a free radical, and to identify it in a vegetal matrix. The structures of the antioxidants in the samples were identified using tandem mass spectrometry and comparison with standards. Fourteen compounds were found to possess potential antioxidant activity, and their free radical scavenging capacities were investigated. The order of scavenging capacity of 14 compounds was compared according to their free radical scavenging rate. 4',5,6,7-Tetrahydroxyflavone (radical scavenging rate: 0.05253 mL mg(-1) s(-1) ) showed the strongest capability for scavenging free radicals. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fast quantification of endogenous carbohydrates in plasma using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.

Science.gov (United States)

Zhu, Bangjie; Liu, Feng; Li, Xituo; Wang, Yan; Gu, Xue; Dai, Jieyu; Wang, Guiming; Cheng, Yu; Yan, Chao

2015-01-01

Endogenous carbohydrates in biosamples are frequently highlighted as the most differential metabolites in many metabolomics studies. A simple, fast, simultaneous quantitative method for 16 endogenous carbohydrates in plasma has been developed using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. In order to quantify 16 endogenous carbohydrates in plasma, various conditions, including columns, chromatographic conditions, mass spectrometry conditions, and plasma preparation methods, were investigated. Different conditions in this quantified analysis were performed and optimized. The reproducibility, precision, recovery, matrix effect, and stability of the method were verified. The results indicated that a methanol/acetonitrile (50:50, v/v) mixture could effectively and reproducibly precipitate rat plasma proteins. Cold organic solvents coupled with vortex for 1 min and incubated at -20°C for 20 min were the most optimal conditions for protein precipitation and extraction. The results, according to the linearity, recovery, precision, matrix effect, and stability, showed that the method was satisfactory in the quantification of endogenous carbohydrates in rat plasma. The quantified analysis of endogenous carbohydrates in rat plasma performed excellently in terms of sensitivity, high throughput, and simple sample preparation, which met the requirement of quantification in specific expanded metabolomic studies after the global metabolic profiling research. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identification of di(ethylhexyl) phthalate as impurity in the analysis by using chromatography gas tandem mass spectrometry

Science.gov (United States)

Pusfitasari, Eka Dian; Hendarsyah, Hendris; Salahuddin, Ariani, Novita

2017-01-01

Di(ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in plastics. Physically DEHP has a low vapor pressure. DEHP can seep into the liquid in direct contact with the plastic wrapping materials, and typically can occur rapidly if extractable into food or non-polar solvents, such as oil, once the food is packaged in PVC packaging materials. DEHP has been analyzed by using gas chromatography which has a high sensitivity level. If the equipment used for the analysis is made from plastic containing DEHP, then it may be possible that DEHP can be extracted and appear on the outcome of the injection. It can interfere with the process of analysis, especially for the analysis of food samples. This study has identified the present of DEHP in the blank injection performed by Gas Chromatography tandem Mass Spectrometry with Selected Ion Monitoring mode (SIM). Researchers are required to verify whether the gas chromatographic system used is ready for the analysis process. In addition, the comparison and calculation of the intensity of the ion fragmentation spectra generated by mass spectrometry detector can be used for the qualitative determination to ensure the presence of the target compound. In this study is also discussed the differences between the high-intensity fragmentation of DEHP and dioctyl phthalate (DOP).

Evaluation of Offline Tandem and Online Solid-Phase Extraction with Liquid Chromatography/Electrospray Ionization-Mass Spectrometry for Analysis of Antibiotics in Ambient Water and Comparison to an Independent Method

Science.gov (United States)

Meyer, M.T.; Lee, E.A.; Ferrell, G.M.; Bumgarner, J.E.; Varns, Jerry

2007-01-01

This report describes the performance of an offline tandem solid-phase extraction (SPE) method and an online SPE method that use liquid chromatography/mass spectrometry for the analysis of 23 and 35 antibiotics, respectively, as used in several water-quality surveys conducted since 1999. In the offline tandem SPE method, normalized concentrations for the quinolone, macrolide, and sulfonamide antibiotics in spiked environmental samples averaged from 81 to 139 percent of the expected spiked concentrations. A modified standard-addition technique was developed to improve the quantitation of the tetracycline antibiotics, which had 'apparent' concentrations that ranged from 185 to 1,200 percent of their expected spiked concentrations in matrix-spiked samples. In the online SPE method, normalized concentrations for the quinolone, macrolide, sulfonamide, and tetracycline antibiotics in matrix-spiked samples averaged from 51 to 142 percent of their expected spiked concentrations, and the beta-lactam antibiotics in matrix-spiked samples averaged from 22 to 76 percent of their expected spiked concentration. Comparison of 44 samples analyzed by both the offline tandem SPE and online SPE methods showed 50 to 100 percent agreement in sample detection for overlapping analytes and 68 to 100 percent agreement in a presence-absence comparison for all analytes. The offline tandem and online SPE methods were compared to an independent method that contains two overlapping antibiotic compounds, sulfamethoxazole and trimethoprim, for 96 and 44 environmental samples, respectively. The offline tandem SPE showed 86 and 92 percent agreement in sample detection and 96 and 98 percent agreement in a presence-absence comparison for sulfamethoxazole and trimethoprim, respectively. The online SPE method showed 57 and 56 percent agreement in sample detection and 72 and 91 percent agreement in presence-absence comparison for sulfamethoxazole and trimethoprim, respectively. A linear regression with

Isobar excitations and low energy spectra of light nuclei

International Nuclear Information System (INIS)

Czerski, P.

1984-01-01

The aim of this investigation is to study the possible influence of inner excitations of nucleons into the Δ(3,3)-resonance on the low lying spectra of light nuclei like 12 C and 16 O. Before we can study the effect of such exotic configurations one has to perform a reliable investigation within the normal nuclear model, which is based on a microscopic theory. This is achieved by performing RPA (Random Phase Approximation) calculations using a realistic residual interaction derived from the Brueckner G-matrix. An efficient parametrisation of the residual interaction is introduced and the reliability of the more phenomenological parametrisations which are generally used is discussed. Within such realistic calculations, the isobar effects are small. (orig.) [de

Identification and Quantification of Glucosinolates in Kimchi by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

Directory of Open Access Journals (Sweden)

Ho Jin Kim

2017-01-01

Full Text Available A novel and simple method for detecting five glucosinolates (glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin, and 4-methoxyglucobrassicin in kimchi was developed using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS. The chromatographic peaks of the five glucosinolates were successfully identified by comparing their retention times, mass spectra. The mobile phase was composed of A (acetonitrile and B (water. As for glucosinolate, the relative quantities were found through sinigrin, and five different compounds that have not been previously discovered in kimchi were observed. Monitoring was carried out on the glucosinolate in 20 kimchis distributed in markets, and this study examined the various quality and quantity compositions of the five components. The glucoalyssin content ranged from 0.00 to 7.07 μmol/g of day weight (DW, with an average content of 0.86 μmol/g of DW, whereas the gluconapin content ranged from 0.00 to 5.85 μmol/g of DW, with an average of 1.17 μmol/g of DW. The content of glucobrassicanapin varied between 0.00 and 11.87 μmol/g of DW (average = 3.03 μmol/g of DW, whereas that of glucobrassicin varied between 0.00 and 0.42 μmol/g of DW (average = 0.06 μmol/g of DW. The 4-methoxyglucobrassicin content ranged from 0.12 to 9.36 μmol/g of DW (average = 3.52 μmol/g of DW. A comparison of the contents revealed that, in most cases, the content of 4-methoxyglucobrassicin was the highest.

Evaluation of Flow-Injection Tandem Mass Spectrometry for Rapid and High-Throughput Quantitative Determination of B-Vitamins in Nutritional Supplements

Energy Technology Data Exchange (ETDEWEB)

Bhandari, Deepak [ORNL; Van Berkel, Gary J [ORNL

2012-01-01

The use of flow-injection electrospray ionization tandem mass spectrometry for rapid and high-throughput mass spectral analysis of selected B-vitamins, viz. B1, B2, B3, B5, and B6, in nutritional formulations was demonstrated. A simple and rapid (~5 min) in-tube sample preparation was performed by adding extraction solvent to a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Automated flow injection introduced 1 L of the extracts directly into the mass spectrometer ion source without chromatographic separation. Sample-to-sample analysis time was 60 s representing significant improvement over conventional liquid chromatography approaches which typically require 25-45 min, and often require more significant sample preparation procedures. Quantitative capabilities of the flow-injection analysis were tested using the method of standard additions and NIST standard reference material (SRM 3280) multivitamin/multielement tablets. The quantity determined for each B-vitamin in SRM 3280 was within the statistical range provided for the respective certified values. The same sample preparation and analysis approach was also applied to two different commercial vitamin supplement tablets and proved to be successful in the quantification of the selected B-vitamins as evidenced by an agreement with the labels values and the results obtained using isotope dilution liquid chromatography/mass spectrometry.

Multimodal MSI in Conjunction with Broad Coverage Spatially Resolved MS² Increases Confidence in Both Molecular Identification and Localization

Energy Technology Data Exchange (ETDEWEB)

Veličković, Dušan; Chu, Rosalie K.; Carrell, Alyssa A. [Biosciences; Thomas, Mathew; Paša-Tolić, Ljiljana; Weston, David J. [Biosciences; Anderton, Christopher R.

2017-12-18

One critical aspect of mass spectrometry imaging (MSI) is the need to confidently identify detected analytes. While orthogonal tandem MS (e.g., LC-MS²) experiments from sample extracts can assist in annotating ions, the spatial information about these molecules is lost. Accordingly, this could cause mislead conclusions, especially in cases where isobaric species exhibit different distributions within a sample. In this Technical Note, we employed a multimodal imaging approach, using matrix assisted laser desorption/ionization (MALDI)-MSI and liquid extraction surface analysis (LESA)-MS²I, to confidently annotate and One critical aspect of mass spectrometry imaging (MSI) is the need to confidently identify detected analytes. While orthogonal tandem MS (e.g., LC-MS2) experiments from sample extracts can assist in annotating ions, the spatial information about these molecules is lost. Accordingly, this could cause mislead conclusions, especially in cases where isobaric species exhibit different distributions within a sample. In this Technical Note, we employed a multimodal imaging approach, using matrix assisted laser desorption/ionization (MALDI)-MSI and liquid extraction surface analysis (LESA)-MS²I, to confidently annotate and localize a broad range of metabolites involved in a tripartite symbiosis system of moss, cyanobacteria, and fungus. We found that the combination of these two imaging modalities generated very congruent ion images, providing the link between highly accurate structural information onfered by LESA and high spatial resolution attainable by MALDI. These results demonstrate how this combined methodology could be very useful in differentiating metabolite routes in complex systems.

Confirmatory analysis method for zeranol, its metabolites and related mycotoxins in urine by liquid chromatography-negative ion electrospray tandem mass spectrometry

International Nuclear Information System (INIS)

Bennekom, E.O. van; Brouwer, L.; Laurant, E.H.M.; Hooijerink, H.; Nielen, M.W.F.

2002-01-01

The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding α- and β-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CCα and CCβ values of 0.02-0.30 and -1 , respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas chromatography high resolution mass spectrometry. Preliminary data show that following a simple matrix solid phase dispersion clean-up, liver samples from poultry will be amenable to this method as well

QuEChERS Purification Combined with Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry for Simultaneous Quantification of 25 Mycotoxins in Cereals

Science.gov (United States)

Sun, Juan; Li, Weixi; Zhang, Yan; Hu, Xuexu; Wu, Li; Wang, Bujun

2016-01-01

A method based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) purification combined with ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS), was optimized for the simultaneous quantification of 25 mycotoxins in cereals. Samples were extracted with a solution containing 80% acetonitrile and 0.1% formic acid, and purified with QuEChERS before being separated by a C18 column. The mass spectrometry was conducted by using positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) models. The method gave good linear relations with regression coefficients ranging from 0.9950 to 0.9999. The detection limits ranged from 0.03 to 15.0 µg·kg−1, and the average recovery at three different concentrations ranged from 60.2% to 115.8%, with relative standard deviations (RSD%) varying from 0.7% to 19.6% for the 25 mycotoxins. The method is simple, rapid, accurate, and an improvement compared with the existing methods published so far. PMID:27983693

High-performance hybrid Orbitrap mass spectrometers for quantitative proteome analysis

DEFF Research Database (Denmark)

Williamson, James C; Edwards, Alistair V G; Verano-Braga, Thiago

2016-01-01

We present basic workups and quantitative comparisons for two current generation Orbitrap mass spectrometers, the Q Exactive Plus and Orbitrap Fusion Tribrid, which are widely considered two of the highest performing instruments on the market. We assessed the performance of two quantitative methods...... on both instruments, namely label-free quantitation and stable isotope labeling using isobaric tags, for studying the heat shock response in Escherichia coli. We investigated the recently reported MS3 method on the Fusion instrument and the potential of MS3-based reporter ion isolation Synchronous...... Precursor Selection (SPS) and its impact on quantitative accuracy. We confirm that the label-free approach offers a more linear response with a wider dynamic range than MS/MS-based isobaric tag quantitation and that the MS3/SPS approach alleviates but does not eliminate dynamic range compression. We...

Design and fabrication of a high performance inorganic tandem solar cell with 11.5% conversion efficiency

International Nuclear Information System (INIS)

Amiri, Omid; Mir, Noshin; Ansari, Fatemeh; Salavati-Niasari, Masoud

2017-01-01

Tandem solar cell is a design that combines two types of solar cells to benefit their advantages. We show a new concept for achieving highly efficient dye sensitized and quantum dot tandem solar cells. The new tandem cell further enhances the performance of the device, leading to a power conversion efficiency more than 11% under 1.5 Air Mass. To the best of our knowledge, this is the first time that the efficiency over 11 percent is achieved based on tandem solar cell. X-ray diffraction, Transmission Electron Microscopy, Scanning Electron Microscopy, Current-Voltage measurments, Intensity modulated photocurrent spectroscopy, intensity modulated photovoltage spectroscopy, Energy Dispersive X-ray spectroscopy, Brunauer-Emmett-Teller, Barrett-Joyner-Halenda and absorption spectroscopy were used to characterize the fabricated solar cells.

Isobaric analogue resonances in the 56Fe(rho,γ)57Co reaction

International Nuclear Information System (INIS)

Elkateb, M.S.

1974-01-01

The excitation function for the reaction 56 Fe(rho,γ) 57 Co has been measured from 1200-3000 KeV proton energy using enriched 56 Fe targets. The resonance strength, ωsub(γ), has been determined for the studied resonances. The absence of the isobaric analogue resonance corresponding to the ground state in 57 Fe is discussed as a result of the present study. A coulomb displacement energy for 57 Co- 57 Fe of 8876 +- 6 KeV is deduced from these measurements. (author)

[Determination of strobilurin fungicides in fruits and their mass fragmentation routes by ultra performance liquid chromatography-tandem mass spectrometry].

Science.gov (United States)

Zhou, Yao; Yang, Huiqin; Shi, Yiyin; Chen, Jiaxian; Zhu, Jian; Deng, Xiaojun; Guo, Dehua

2017-09-08

A method was developed for the simultaneous determination of six strobilurin fungicide ( E -metominostrobin, azoxystrobin, kresoxim-methyl, picoxystrobin, pyraclostrobin and trifloxystrobin) residues in orange, banana, apple and pineapple samples by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The fragmentation routes of all the compounds were explained by the aid of a fragment predicting software ACD Lab/MS Fragmenter. The samples were extracted by acetonitrile, then cleaned up by amino solid phase extraction cartridges (SupelClean LC-NH 2 ). The extracts were separated on a ACQUITY UPLC BEH C 18 column (50 mm×2.1 mm, 1.7 μm) with gradient elution. Acetonitrile containing 0.1% (v/v) formic acid and 10 mmol/L ammonium acetate containing 0.1% (v/v) formic acid were used as mobile phases. The samples were detected by electrospray ionization (ESI)-MS/MS in positive ion and multiple reaction monitoring (MRM) mode, quantified by external standard method. Good linearities were obtained in the range of 5-100 μg/L (for pyraclostrobin, 1-20 μg/L) with correlation coefficients ( r 2 ) greater than 0.999. The recoveries ranged from 60.4% to 120% with the relative standard deviations between 2.15% and 15.1% ( n =6). The developed method can meet the inspection of the six strobilurin residues in the orange, banana, apple and pineapple samples.

Mapping Isobaric Aging onto the Equilibrium Phase Diagram.

Science.gov (United States)

Niss, Kristine

2017-09-15

The linear volume relaxation and the nonlinear volume aging of a glass-forming liquid are measured, directly compared, and used to extract the out-of-equilibrium relaxation time. This opens a window to investigate how the relaxation time depends on temperature, structure, and volume in parts of phase space that are not accessed by the equilibrium liquid. It is found that the temperature dependence of relaxation time is non-Arrhenius even in the isostructural case-challenging the Adam-Gibbs entropy model. Based on the presented data and the idea that aging happens through quasiequilibrium states, we suggest a mapping of the out-of-equilibrium states during isobaric aging to the equilibrium phase diagram. This mapping implies the existence of isostructural lines in the equilibrium phase diagram. The relaxation time is found to depend on the bath temperature, density, and a just single structural parameter, referred to as an effective temperature.

Comprehensive and accurate tracking of carbon origin of LC-tandem mass spectrometry collisional fragments for 13C-MFA.

Science.gov (United States)

Kappelmann, Jannick; Klein, Bianca; Geilenkirchen, Petra; Noack, Stephan

2017-03-01

In recent years the benefit of measuring positionally resolved 13 C-labeling enrichment from tandem mass spectrometry (MS/MS) collisional fragments for improved precision of 13 C-Metabolic Flux Analysis ( 13 C-MFA) has become evident. However, the usage of positional labeling information for 13 C-MFA faces two challenges: (1) The mass spectrometric acquisition of a large number of potentially interfering mass transitions may hamper accuracy and sensitivity. (2) The positional identity of carbon atoms of product ions needs to be known. The present contribution addresses the latter challenge by deducing the maximal positional labeling information contained in LC-ESI-MS/MS spectra of product anions of central metabolism as well as product cations of amino acids. For this purpose, we draw on accurate mass spectrometry, selectively labeled standards, and published fragmentation pathways to structurally annotate all dominant mass peaks of a large collection of metabolites, some of which with a complete fragmentation pathway. Compiling all available information, we arrive at the most detailed map of carbon atom fate of LC-ESI-MS/MS collisional fragments yet, comprising 170 intense and structurally annotated product ions with unique carbon origin from 76 precursor ions of 72 metabolites. Our 13 C-data proof that heuristic fragmentation rules often fail to yield correct fragment structures and we expose common pitfalls in the structural annotation of product ions. We show that the positionally resolved 13 C-label information contained in the product ions that we structurally annotated allows to infer the entire isotopomer distribution of several central metabolism intermediates, which is experimentally demonstrated for malate using quadrupole-time-of-flight MS technology. Finally, the inclusion of the label information from a subset of these fragments improves flux precision in a Corynebacterium glutamicum model of the central carbon metabolism.

Use of on-line supercritical fluid extraction-supercritical fluid chromatography/tandem mass spectrometry to analyze disease biomarkers in dried serum spots compared with serum analysis using liquid chromatography/tandem mass spectrometry.

Science.gov (United States)