DOCSLIB.ORG

Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometer As a New Tool for Organic Chemists Jan St

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometer As a New Tool for Organic Chemists Jan St NEW TOOLS IN SYNTHESIS 249 Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometer as a New Tool for Organic Chemists Jan St. Pyrek University of Kentucky Mass Spectrometry Facility, ASTeCC Bldg, Lexington, KY 40506-0286, USA. E-mail: jpyrek1@pop.uky.edu Received 16 December 1998 This article is dedicated to Professor Zofia Kasprzyk for her 81 birthday 1 Introduction Abstract: Currently, mass spectral determination of molecular weights and elemental compositions of synthetic products is a com- mon practice. It is aided by truly impressive developments in meth- Mass spectrometry (MS) is the technique that renders ods and instrumentation enabling to characterize great variety of mass-to-charge ratios (m/z) and relative intensities of ions compounds including even those of a relatively high molecular formed (with exceptions), separated, and detected in the weight. Confidence in such measurements, however, depends upon high vacuum. The remarkable analytical potentials of MS selecting a suitable ionization method, unambiguous identification have been immediately recognized by its inventor J. J. of a molecular-type ion, and the adequate precision of mass deter- Thomson and, in years immediately following the First minations. This review addresses major aspects of the ion formation and analysis with special attention given to the ion-cyclotron reso- World War, the detection and precise characterization of nance. This powerful technique, different in its principle from most isotopes of almost all elements have been achieved em- other methods of ion analysis, offers a superb combination of ion ploying the very first mass spectrographs and spectrome- manipulation and measurement parameters and full compatibility ters.1 With some delay, however, these seminal with an array of ionization methods. discoveries have been followed by a systematic effort to Key words: mass spectrometry, ultra-high resolution mass spec- analyze organic compounds. Ever since, thanks to a trometry, ion-cyclotron-resonance, soft ionization, stable isotopes, steady progress in techniques and instrumentation, MS molecular weight determination. continues to serve in a variety of inorganic and organic ap- plications. Moreover, by gaining truly astonishing capa- 1. Introduction bilities in terms of ionization, mass range, sensitivity, and 2. Ion analysis 2.1. Types of mass analyzers accuracy, MS methods cover classes of compounds that 2.2. Compatibility of ion sources with mass analyzers originally have been considered as entirely unsuitable for 2.3. Fourier Transform-Ion Cyclotron Resonance-Mass such an analysis.2 Spectrometer Still, as exemplified by the recent synthesis of two diter- 2.3.1. Overview 3 2.3.2. Trapping ions in the ICR-cell penoids, synthetic work can be carried out with the com- 2.3.3. Detection of the trapped ions plete omission of MS. As a rule, however, MS data are 2.3.4. Getting ions into the ICR Cell used to confirm MW and to replace elemental analyses of 2.4. Tandem mass spectrometry the final reaction products. Only seldom, synthetic publi- 2.4.1. Tandem mass spectrometry with magnetic-sectors and cations include detailed spectral interpretations and use quadrupoles more advanced MS techniques. This low visibility of MS 2.4.2. Tandem-MS with FT-ICR-MS contrasts with the structure elucidation of natural and met- 3. Ion formation 3.1. Overview abolic products and, more recently, with the characteriza- 3.2. Electron impact ionization tion and sequencing of linear biopolymers. Still, an early 3.3. Chemical ionization implementation of MS analysis in the synthetic practice 3.4. Fast atom bombardment may greatly facilitate structural assignments well before 3.5. Matrix assisted laser desorption/ionization time and effort is invested in separation and purification 3.6. Cationization of products. MS analysis, especially when combined with 3.7. Electrospray ionization the on-line chromatography, provides an advantage in 4. Mass spectrometry and molecular weight determination 4.1. Stable isotopes and molecular ions confirming identity and purity of substrates, in finding if 4.2. Isotopic depletion and substitution the expected compounds are formed, in identifying inter- 4.3. High or ultra-high resolution? mediates and by-products and, finally, in guiding through- 4.4. Mass measurement accuracy out their isolation and purification. Such an extensive use 4.5. Can molecular weight be unequivocally determined by of MS methods, however, requires an access to instrumen- mass spectrometry? tation supported by the comprehension of novel and tradi- tional methods with the full awareness of their inherent limitations. This review, in an attempt to assess the relevance of MS in establishing MW, surveys selected methods of ion for- Synlett 1999, No. 2, 249–266 ISSN 0936-5214 © Thieme Stuttgart · New York 250 J. St. Pyrek NEW TOOLS IN SYNTHESIS mation and analysis. It gives special attention to Fourier of ion sources and in some configurations must work with Transform-Ion Cyclotron Resonance-Mass Spectrometry interfaces handling a considerable flow of solvents. More- (FT-ICR-MS), an advanced method providing an unprec- over, for techniques such as ESI (Section 3.7) mass ana- edented ultra-high mass resolution, high sensitivity, and lyzers of an extended mass range (2,000-4,000 u) and versatile MS/MS, but still only seldom used in a routine resolution depicting multiply charged ions are highly de- characterization of organic compounds. Easier access to sirable. Although magnetic-sector instruments usually FT-ICR-MS instruments, by offering gains analogous to furnish all such necessary parameters, quadrupoles and those of now routine use of the high field NMR, should ion traps4 prevail as detectors in chromatographic applica- help in traditional and combinatorial synthesis aimed at tions. Newer solutions to LC and GC interfacing come targets of ever increasing MW and architectural complex- from the recent developments in time-of-flight (TOF) in- ity. struments offering very high rate of spectral repetitions and good resolution. Still, registering spectra at medium and high resolution, rather than a unit resolution, provides 2 Ion Analysis richer structural information and considerably improves specificity of the detection in analytical applications. While a simple, on-line MS detection characterizes com- 2.1 Types of mass analyzers pounds by their chromatographic mobility and spectra, Selection of an ion analyzer (Table 1) results from spe- tandem-MS (MS/MS) measurements (Section 2.4) pro- cific analytical tasks and compatibility with the mode of vide another dimension that delineates specific parent- sample introduction and ionization. For every mass spec- daughter (or according to PC nomenclature, “precursor- trometer, configuration of its three principal parts, ion product”) ion relations. This information considerably source, ion analyzer, and ion detector, determines mass augments selectivity in the detection of selected targets range, scanning speed, mass resolution, mass accura- whereas for novel compounds may help in their structure cy, sensitivity, and the dynamic range of ion intensity elucidation. measurements. As exemplified by interfacing MS detec- Recent developments are aimed primarily at the emerging tion with chromatographic methods, some of these para- applications of soft ionization methods pertinent to medi- meters can be compromised, especially in instrument ded- um and high MW biological compounds. There is partic- icated to a single task. Thus, for gas chromatography- ular attention paid to the TOF and ion trap instruments, mass spectrometry (GC-MS), mass analyzers capable of mostly because of their great simplicity, and to FT-ICR, fast scanning to only about 1,000 u and resolving power mostly because of its superb parameters. Yet, high resolu- separating only the adjacent ions (unit resolution) may be tion magnetic-sector instruments still suit well all major quite adequate. Such instruments may operate only with ionization methods including those that are most frequent- EI (Section 3.2) but require good sensitivity and broad dy- ly used in the organic MS and, in terms of resolution and namic range defining ions that differ in their intensity by dynamic range, provide benchmark spectra. Even older 2-3 orders, in components that may differ by another 2-3 sector instruments upgraded with new data systems and orders. For a comparison, LC-MS utilizes greater variety new ion sources may still offer very good performance. Biographical Sketch Jan Pyrek, born in 1942 in Then, still in the same Insti- Currently, as a faculty in the Jaslo - a subcarpatian town, tute and while visiting labo- College of Pharmacy, he di- was educated in Krakow and ratories of Professors G. rects the MS-Facility at the Warsaw. He participated in Jommi (University of Mi- University of Kentucky. He Polish Chemistry Olympi- lan) and E. Wenkert (Rice has authored over 90 publi- ads as early as 1957. He University), he continued to cations concerned mostly studied and worked in the work on natural products. In with structure, metabolism, Biochemistry Department of 1979, he joined the faculty and synthesis of various nat- Warsaw University (1960- of the University of Texas at ural products. Apart from 7) under the direction of Houston, initiating new in- science, he has a long inter- Prof. Zofia Kasprzyk. Sub- terests in steroids, bile acids, est in art and, while living in sequently, he obtained his and biomedical application rural Kentucky with his wife Ph.D. degree
Load more

Recommended publications
  • Gas Cluster Ion Beams for Secondary Ion Mass Spectrometry
    AC11CH02_Winograd ARI 3 May 2018 15:10 Annual Review of Analytical Chemistry Gas Cluster Ion Beams for Secondary Ion Mass Spectrometry Nicholas Winograd Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA; email: nxw@psu.edu Annu. Rev. Anal. Chem. 2018. 11:29–48 Keywords First published as a Review in Advance on bioimaging, cluster ion beams, phospholipids, instrumentation, molecular February 28, 2018 depth profiling, molecular dynamics computer simulations The Annual Review of Analytical Chemistry is online at anchem.annualreviews.org Abstract https://doi.org/10.1146/annurev-anchem- Gas cluster ion beams (GCIBs) provide new opportunities for bioimaging 061516-045249 Annual Rev. Anal. Chem. 2018.11:29-48. Downloaded from www.annualreviews.org and molecular depth profiling with secondary ion mass spectrometry (SIMS). Access provided by Pennsylvania State University on 02/26/19. For personal use only. Copyright c 2018 by Annual Reviews. These beams, consisting of clusters containing thousands of particles, ini- All rights reserved tiate desorption of target molecules with high yield and minimal fragmen- tation. This review emphasizes the unique opportunities for implementing these sources, especially for bioimaging applications. Theoretical aspects of ANNUAL REVIEWS Further the cluster ion/solid interaction are developed to maximize conditions for Click here to view this article's online features: successful mass spectrometry. In addition, the history of how GCIBs have • Download figures as PPT slides become practical laboratory tools is reviewed. Special emphasis is placed on • Navigate linked references • Download citations the versatility of these sources, as size, kinetic energy, and chemical compo- • Explore related articles • Search keywords sition can be varied easily to maximize lateral resolution, hopefully to less than 1 micron, and to maximize ionization efficiency.
    [Show full text]
  • Devices for Mass Spectrometry on a Chip
    DEVICES FOR MASS SPECTROMETRY ON A CHIP Title: Professor Name: Richard R.A.Syms Affiliation/Address: EEE Dept., Imperial College London Phone: +44-207-594-6203 E-mail: r.syms@imperial.ac.uk Devices for mass spectrometry on a chip Synonyms Mass spectrometer, mass analyser Definition A mass spectrometer is a vacuum analytical instrument that uses electric or magnetic fields or a mixture of the two to separate ions based on the ratio of their mass m to their charge q. A distinction is made between mass spectrometers, which produce a serially scanned output, and mass spectrographs, which produce a parallel (and sometimes graphical) output. The mass-to charge ratio is often written as m/z, where q = ze, e = 1.6 x 10-19 C is the electronic charge and z is the charge number. The ions are created from analyte molecules by processes that give rise to a characteristic pattern of fragments, in addition to the molecular ion itself, allowing a mass spectrometer to be used for chemical identification, compositional quantification and structural analysis. Performance is characterized in terms of the mass range (defined by the maximum mass mmax that can be measured), the mass resolution (defined as m/∆m, where ∆m is the uncertainty in the mass being measured) and the PAGE 1/25 DEVICES FOR MASS SPECTROMETRY ON A CHIP sensitivity. Applications include analytical chemistry, process and pollution monitoring, forensic science, the detection of drugs, chemical and biochemical weapons, and space exploration. In some cases, high performance is essential, while in others, low cost, small size, and portability are more desirable.
    [Show full text]
  • Stability of Metal Nanoclusters - Shells of Atoms and Electrons
    2145-1 Spring College on Computational Nanoscience 17 - 28 May 2010 Stability of metal nanoclusters - shells of atoms and electrons Hannu HAKKINEN Nanoscience Center, Dept. of Physics and Chemistry University of Jyvaskyla Finland Stability of metal nanoclusters – shells of atoms and electrons Hannu Häkkinen Lecture 1 Trieste 5/2010 Hannu Häkkinen, Nanoscience Center, University of Jyväskylä Cluster science – at the heart of ”Nano” ! nanocatalysts Thermodynamics Supported of small systems nanoparticles Understanding the size- dependent properties of clusters in vacuum Reaction centers Cluster in enzymes materials Passivated nanoparticles Hannu Häkkinen, Nanoscience Center, University of Jyväskylä 1 Some literature !! R. L. Johnston, Atomic and Molecular Clusters, Taylor & Francis (2002). !! W. A. de Heer, The physics of simple metal clusters: Experimental aspects and simple models, Rev. Mod. Phys 65, 611 (1993). !! M. Brack, The physics of simple metal clusters: Self-consistent jellium model and semiclassical approaches, Rev. Mod. Phys. 65, 677 (1993). !! F. Baletto, R. Ferrando, Structural properties of nanoclusters: Energetic, thermodynamic, and kinetic effects, Rev. Mod. Phys. 77, 371 (2005). !! T. P. Martin, Shells of atoms, Phys. Rep. 273, 199 (1996). !! L. D. Marks, Experimental studies of small particle structures, Rep. Prog. Phys. 57, 603 (1994). Hannu Häkkinen, Nanoscience Center, University of Jyväskylä Manufacturing & analysis Hannu Häkkinen, Nanoscience Center, University of Jyväskylä 2 Cluster sources !! Seeded supersonic
    [Show full text]
  • Chip-Scale Quadrupole Mass Filters for a Micro-Gas Analyzer
    Chip-Scale Quadrupole Mass Filters for a Micro-Gas Analyzer by Kerry Cheung B.S., Applied and Engineering Physics Cornell University, 2003 S.M., Electrical Engineering and Computer Science Massachusetts Institute of Technology, 2005 Submitted to the Department of Electrical Engineering and Computer Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering and Computer Science at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 2009 © 2009 Massachusetts Institute of Technology All rights reserved Author__________________________________________________________________ Department of Electrical Engineering and Computer Science May 22, 2009 Certified by______________________________________________________________ Akintunde I. Akinwande Professor of Electrical Engineering and Computer Science Thesis Supervisor Accepted by_____________________________________________________________ Terry P. Orlando Professor of Electrical Engineering and Computer Science Chairman, Department Committee on Graduate Students 2 Chip-Scale Quadrupole Mass Filters for a Micro-Gas Analyzer by Kerry Cheung Submitted to the Department of Electrical Engineering and Computer Science on May 22, 2009 in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering and Computer Science Abstract Mass spectrometers are powerful analytical instruments that serve as the gold standard for chemical analysis. This tool has numerous applications ranging from national security, industrial
    [Show full text]
  • 1 History of Mass Spectrometric Techniques
    1 History of Mass Spectrometric Techniques In its history, mass spectrometry has passed through fascinating scientific epochs of development and supplied important contributions to the world view in quite different fields of science (espe- cially in the life sciences, environmental science and technology, material and nuclear sciences, geosciences, cosmochemistry,1 planetary and forensic sciences) and in basic studies in chemistry and physics. Mass spectrometry is more than 100 years old and has yielded basic results and profound insights for the development of atomic physics. The rapid development of nuclear physics, in particular, would be unthinkable without the application of mass spectrometric methods. Mass spectrometry has contributed to conclusive evidence for the hypothesis of the atomic structure of matter. So far mass spectrometry has supplied specific results on the structure of the nucleus of atoms. Nobel prizes have been awarded to a number of scientists (Thomson, Wien, Aston, Paul, Fenn and Tanaka) associated with the birth and development of mass spectrometry, or in which mass spectrometry has aided an important discovery (e.g., for the discovery of fullerenes by Curl, Kroto and Smalley). Relevant preliminary work for the development of mass spectrography started with Goldstein’s discovery of anode rays, which are positive charged gas-phase ions, in gas discharge in the mid- 1980s. The experimental arrangement of Goldstein’s glow discharge tube as the simplest possible ion source is shown in Figure 1.3 and was firstly published in the ‘Sitzungsbericht der Königlich- Preußischen Akademie der Wissenschaften’ in 1886.2 Goldstein’s method for generating positively charged ions in a gas discharge was used in the early mass analysis measurements of Wien,3 Thomson4 and Aston.5 In 1898 Wien analyzed the anode rays by magnetic deflection and found that these rays carried a positive charge.
    [Show full text]
  • (12) United States Patent (10) Patent No.: US 8,507,849 B2 Brown (45) Date of Patent: Aug
    US008507849B2 (12) United States Patent (10) Patent No.: US 8,507,849 B2 BrOWn (45) Date of Patent: Aug. 13, 2013 (54) MASS SPECTROMETER (56) References Cited (75) Inventor: Jeffery Mark Brown, Cheshire (GB) U.S. PATENT DOCUMENTS 6,300,627 B1 10/2001 Koster et al. (73) Assignee: Micromass UK Limited, Manchester 6,512,226 B1 1/2003 Loboda et al. (GB) 6,534,764 B1 3/2003 Verentchikov et al. 6,627,877 B1 9, 2003 Davis et al. 6,900,430 B2 5/2005 Okumura et al. (*) Notice: Subject to any disclaimer, the term of this 2002/0027194 A1 3/2002 Holle et al. ................... 250,287 patent is extended or adjusted under 35 2004/0232327 A1 11/2004 Bateman et al. U.S.C. 154(b) by 804 days. 2005/0242279 A1* 11/2005 Verentchikov ................ 250,287 2007/0034794 A1 2/2007 Cotter et al. .................. 250,287 (21) Appl. No.: 11/721,755 * cited by examiner PCT Fled: Dec. 19, 2005 (22) FOREIGN PATENT DOCUMENTS (86) PCT NO.: PCT/GB2OOS/OO4911 EP 1306881 5, 2003 WO 2004O21386 8, 2003 S371 (c)(1), WO 20040O8481 1, 2004 (2), (4) Date: Jul. 3, 2009 OTHER PUBLICATIONS (87) PCT Pub. No.: WO2006/064280 Bateman, R. H. et al; A Combined Magnetic Sector-Time-of-flight Mass Spectrometer for Structural Determination Studies by Tandem PCT Pub. Date: Jun. 22, 2006 Mass Spectrometry; Rapid Communications in Mass Spectrometry, (65) Prior Publication Data vol. 9, 1227-1233 (1995). US 2009/O29.4642 A1 Dec. 3, 2009 Primary Examiner — Nicole Ippolito (74) Attorney, Agent, or Firm — Diederiks & Whitelaw, PLC Related U.S.
    [Show full text]
  • Example: Accelerator Mass Spectrometry (AMS)
    Example: Accelerator mass spectrometry (AMS) Today’s schedule: • What is AMS used for? • How does it work? • Assignments: dead-line 21 December Example: Accelerator mass spectrometry (AMS) • Archeology • Geology • Medicine • Food chemistry 3H 14C 36 • Radiation protection Cl • Ecology 10 Be 59Ni • Radioecology • Aerosol science 26Al • Pharmaceutical development • Bomb-pulse dating How is 14C created? Cosmic rays 14 14 + C (carbon-14) Modern carbon O2 CO2 14 99% 12C N (nitrogen-14) 1% 13C 14CO 10-10% 14C 14CO O2 2 14 14 2 C + O2 CO2 O2 14 CO2 O2 14C 14N + -radiation T1/2=5730 years 14 How to measure C? (T1/2=5730 years) ”Modern”carbon: 99% 12C Decay measurement: • several days of measuring time 13 1% C • 1 g carbon 10-10 % 14C 14 decays/minute 1 gram of modern carbon 14C 14N + -radiation 60 000 million atoms AMS measurement: • < 1 hour of measuring time • 10 µg - 1 mg carbon Why not conventional mass spectrometry? BR=mv/q=(2mE)1/2/q The 14C signal will drown in a background of interfering isobars (ions with M=14, e.g. 13CH)! Two types of AMS systems • Tandem AMS (usually called just AMS): developed in the late 1970ies • Single Stage AMS (SSAMS): first commercial system installed in 2004 in Lund The exercise is on SSAMS! Accelerator Mass Spectrometry (AMS) Tandem AMS Ion source Detector Counting atoms with tandem-AMS: refined mass spectrometry Example: a large 3 MV system 3 MV Ion source tandem accelerator with carbon Velocity samples filter Particle Dipolmagnets detector Mass separator • Measures 14C/13C/12C: gives activity ( age) • Measuring
    [Show full text]
  • Magnetically Enhanced Quadrupole Mass Spectrometer
    Magnetically Enhanced Quadrupole Mass Spectrometer Thesis submitted in accordance with the requirements of the University of Liverpool for the degree of Doctor in Philosophy by Simon Maher Department of Electrical Engineering and Electronics University of Liverpool September 2013 Synopsis The Quadrupole Mass Filter (QMF) is the key component of a Quadrupole Mass Spectrometer (QMS) first described by Nobel laureate Wolfgang Paul and co- worker Helmut Steinwedel in 1953. The QMS remains a widely used analytical tool for separating charged species in space according to their mass-to-charge ratio, with an extensive range of applications in both industry and research. In the original work of Paul and Steinwedel much emphasis was placed on the fact that the QMF separates ions due to the quadrupolar electric field (comprising dc and ac components) and without the use of magnetic fields. In the present thesis both experimental and theoretical work is presented, to demonstrate that the application of a magnetic field to a QMS enhances device performance. Theoretical work has focussed on the analytical investigation of the Mathieu equation for this particular case. This has led to an extensive simulation study of a QMS under the application of static and dynamic magnetic fields. A method is described that enables the three-dimensional (3D) fields of a simple QMF to be determined to a high accuracy. The technique produces accurate field values and was used to investigate fringe field effects particularly at the entrance to the QMF where they can often be detrimental to performance. Moreover, a two- dimensional (2D) software model was used to study the behaviour of the QMF and modified to incorporate the effect of applying a magnetic field.
    [Show full text]
  • Development of a Primary Ion Column for Mass Spectrometry-Based Surface Analysis Raul A
    Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 7-1-2016 Development of a Primary Ion Column for Mass Spectrometry-Based Surface Analysis Raul A. Villacob rvill028@fiu.edu DOI: 10.25148/etd.FIDC000761 Follow this and additional works at: https://digitalcommons.fiu.edu/etd Part of the Analytical Chemistry Commons Recommended Citation Villacob, Raul A., "Development of a Primary Ion Column for Mass Spectrometry-Based Surface Analysis" (2016). FIU Electronic Theses and Dissertations. 2561. https://digitalcommons.fiu.edu/etd/2561 This work is brought to you for free and open access by the University Graduate School at FIU Digital Commons. It has been accepted for inclusion in FIU Electronic Theses and Dissertations by an authorized administrator of FIU Digital Commons. For more information, please contact dcc@fiu.edu. FLORIDA INTERNATIONAL UNIVERSITY Miami, Florida DEVELOPMENT OF A PRIMARY ION COLUMN FOR MASS SPECTROMETRY- BASED SURFACE ANALYSIS A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in CHEMISTRY by Raul A. Villacob 2016 To: Dean Michael R. Heithaus choose the name of dean of your college/school College of Arts, Sciences and Education choose the name of your college/school This thesis, written by Raul A. Villacob, and entitled Development of a Primary Ion Column for Mass Spectrometry-based Surface Analysis, having been approved in respect to style and intellectual content, is referred to you for judgment. We have read this thesis and recommend that it be approved. _______________________________________ Piero R. Gardinali _______________________________________ Jeffrey Joens _______________________________________ Francisco A.
    [Show full text]
  • Mass Spectrometry: Forming Ions, to Identifying Proteins and Their Modifications
    Mass spectrometry: forming ions, to identifying proteins and their modifications Stephen Barnes, PhD 4-7117 sbarnes@uab.edu S Barnes-UAB 1/20/06 Introduction to mass spectrometry • Class 1 - Biology and mass spectrometry – Why is mass spectrometry so important? – Short history of mass spectrometry – Ionization and measurement of ions • Class 2 - The mass spectrum – What is a mass spectrum? – Interpreting ESI and MALDI-TOF spectra – Combining peptide separation with mass spectrometry – MALDI mass fingerprinting – Tandem mass spectrometry and peptide sequencing S Barnes-UAB 1/20/06 1 Goals of research on proteins • To know which proteins are expressed in each cell, preferably one cell at a time • Major analytical challenges – Sensitivity - no PCR reaction for proteins – Larger number of protein forms than open reading frames – Huge dynamic range (109) – Spatial and time-dependent issues S Barnes-UAB 1/20/06 Changes at the protein level • To know how proteins are modified, information that cannot necessarily be deduced from the nucleotide sequence of individual genes. • Modification may take the form of – specific deletions (leader sequences), – enzymatically induced additions and subsequent deletions (e.g., phosphorylation and glycosylation), – intended chemical changes (e.g., alkylation of sulfhydryl groups), – and unwanted chemical changes (e.g., oxidation of sulfhydryl groups, nitration, etc.). S Barnes-UAB 1/20/06 2 Proteins once you have them Protein structure and protein-protein interaction – to determine how proteins assemble in solution – how they interact with each other – Transient structural and chemical changes that are part of enzyme catalysis, receptor activation and transporters S Barnes-UAB 1/20/06 So, what you need to know about mass spec • Substances have to be ionized to be detected.
    [Show full text]
  • Beams of Atomic Clusters: Effects on Impact with Solids
    Rev.Adv.Mater.Sci.Beams of atomic clusters: 11 (2006) effects 19-45 on impact with solids 19 BEAMS OF ATOMIC CLUSTERS: EFFECTS ON IMPACT WITH SOLIDS V.N. Popok and E.E.B. Campbell Department of Physics, Göteborg University, 41296 Göteborg, Sweden Received: May 12, 2005 Abstract. A state-of-the-art review in the field of cluster beams and energetic cluster-surface interaction is presented. Ionised cluster beams are considered to be a controllable and versatile tool for modification and processing of surfaces and near-surface layers on an atomic scale as an alternative to ion implantation, ion assisted deposition and some other methods. A brief introduction to the history of cluster beams is given as well as a discussion of the capabilities of cluster beams for a variety of applications in material science, electronics and optics. Techniques for producing atomic and molecular clusters are described. Energetic cluster deposition and cluster implantation as well as related physical effects are the main emphasis of the review. In the final part of the paper the attention is focused on the study of surface erosion (crater formation) under energetic cluster ion impact. 1. INTRODUCTION tronic, optical, magnetic and other properties that are quite different from those of molecules or con- Atomic (or molecular) clusters are aggregates of a densed matter and that can be of great interest for few up to tens of thousands of atoms (or molecules) practical applications in nanotechnology [4-9]. With that show properties intermediate between those clusters consisting of up to thousands of atoms it is of individual atoms (or molecules), with discrete possible to transport and locally deposit a large energy states, and bulk matter characterised by amount of material, providing an advanced method continua or bands of states.
    [Show full text]
  • Development of Mass Spectrometers from Thomson and Aston to Present
    International Journal of Mass Spectrometry 349–350 (2013) 9–18 Contents lists available at ScienceDirect International Journal of Mass Spectrometry j ournal homepage: www.elsevier.com/locate/ijms Development of mass spectrometers from Thomson and Aston to present a,b,∗ G. Münzenberg a GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany b Manipal University, Manipal 576106, Karnataka, India a r a t i b s c t l e i n f o r a c t Article history: Mass spectrometry contributed to the understanding of the structure of elementary matter including Received 6 February 2013 the isotopic nature of the chemical elements, isotopic abundances, nuclear binding, and the investiga- Received in revised form 7 March 2013 tion of nuclides far-off stability. In this paper the continuous development of mass spectrometers from Accepted 11 March 2013 W. Wien’s first mass analysis to J.J. Thomson’s discovery of isotopes, F.W. Aston’s mass spectrometers, Available online 19 March 2013 and the Mattauch–Herzog double focusing spectrometer to the present rare isotope facilities will be dis- cussed. Separators with magnetic sector fields e.g. from A.O. Nier and the Oak Ridge separator batteries Keywords: for large-scale isotope production are included. The first applications to chemistry and geochemistry will Mass measurements be mentioned briefly. The key role of the development of ion optics from the first geometrical calcula- Sector mass spectrometers tions towards modern matrix method is addressed. Finally recent developments of mass spectrometers Historical developments for basic nuclear research including ISOL and in-flight separators for rare-isotope facilities and mass JEL classification: spectrometry with cooled and stored ions will be presented.
    [Show full text]