1 Introduction to Mass Spectrometry, a Tutorial Wilfried M.A
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An Introduction to Isotopic Calculations John M
An Introduction to Isotopic Calculations John M. Hayes ([email protected]) Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA, 30 September 2004 Abstract. These notes provide an introduction to: termed isotope effects. As a result of such effects, the • Methods for the expression of isotopic abundances, natural abundances of the stable isotopes of practically • Isotopic mass balances, and all elements involved in low-temperature geochemical • Isotope effects and their consequences in open and (< 200°C) and biological processes are not precisely con- closed systems. stant. Taking carbon as an example, the range of interest is roughly 0.00998 ≤ 13F ≤ 0.01121. Within that range, Notation. Absolute abundances of isotopes are com- differences as small as 0.00001 can provide information monly reported in terms of atom percent. For example, about the source of the carbon and about processes in 13 13 12 13 atom percent C = [ C/( C + C)]100 (1) which the carbon has participated. A closely related term is the fractional abundance The delta notation. Because the interesting isotopic 13 13 fractional abundance of C ≡ F differences between natural samples usually occur at and 13F = 13C/(12C + 13C) (2) beyond the third significant figure of the isotope ratio, it has become conventional to express isotopic abundances These variables deserve attention because they provide using a differential notation. To provide a concrete the only basis for perfectly accurate mass balances. example, it is far easier to say – and to remember – that Isotope ratios are also measures of the absolute abun- the isotope ratios of samples A and B differ by one part dance of isotopes; they are usually arranged so that the per thousand than to say that sample A has 0.3663 %15N more abundant isotope appears in the denominator and sample B has 0.3659 %15N. -
Mass Spectrometry: Quadrupole Mass Filter
Advanced Lab, Jan. 2008 Mass Spectrometry: Quadrupole Mass Filter The mass spectrometer is essentially an instrument which can be used to measure the mass, or more correctly the mass/charge ratio, of ionized atoms or other electrically charged particles. Mass spectrometers are now used in physics, geology, chemistry, biology and medicine to determine compositions, to measure isotopic ratios, for detecting leaks in vacuum systems, and in homeland security. Mass Spectrometer Designs The first mass spectrographs were invented almost 100 years ago, by A.J. Dempster, F.W. Aston and others, and have therefore been in continuous development over a very long period. However the principle of using electric and magnetic fields to accelerate and establish the trajectories of ions inside the spectrometer according to their mass/charge ratio is common to all the different designs. The following description of Dempster’s original mass spectrograph is a simple illustration of these physical principles: The magnetic sector spectrograph PUMP F DD S S3 1 r S2 Fig. 1: Dempster’s Mass Spectrograph (1918). Atoms/molecules are first ionized by electrons emitted from the hot filament (F) and then accelerated towards the entrance slit (S1). The ions then follow a semicircular trajectory established by the Lorentz force in a uniform magnetic field. The radius of the trajectory, r, is defined by three slits (S1, S2, and S3). Ions with this selected trajectory are then detected by the detector D. How the magnetic sector mass spectrograph works: Equating the Lorentz force with the centripetal force gives: qvB = mv2/r (1) where q is the charge on the ion (usually +e), B the magnetic field, m is the mass of the ion and r the radius of the ion trajectory. -
Gas Chromatography-Mass Spectroscopy
Gas Chromatography-Mass Spectroscopy Introduction Gas chromatography-mass spectroscopy (GC-MS) is one of the so-called hyphenated analytical techniques. As the name implies, it is actually two techniques that are combined to form a single method of analyzing mixtures of chemicals. Gas chromatography separates the components of a mixture and mass spectroscopy characterizes each of the components individually. By combining the two techniques, an analytical chemist can both qualitatively and quantitatively evaluate a solution containing a number of chemicals. Gas Chromatography In general, chromatography is used to separate mixtures of chemicals into individual components. Once isolated, the components can be evaluated individually. In all chromatography, separation occurs when the sample mixture is introduced (injected) into a mobile phase. In liquid chromatography (LC), the mobile phase is a solvent. In gas chromatography (GC), the mobile phase is an inert gas such as helium. The mobile phase carries the sample mixture through what is referred to as a stationary phase. The stationary phase is usually a chemical that can selectively attract components in a sample mixture. The stationary phase is usually contained in a tube of some sort called a column. Columns can be glass or stainless steel of various dimensions. The mixture of compounds in the mobile phase interacts with the stationary phase. Each compound in the mixture interacts at a different rate. Those that interact the fastest will exit (elute from) the column first. Those that interact slowest will exit the column last. By changing characteristics of the mobile phase and the stationary phase, different mixtures of chemicals can be separated. -
Tandem Mass Spectrometry (MS–MS)
Advanced Analytical Chemistry Lecture 22 Chem 4631 Tandem Mass Spectrometry (MS–MS) Tandem mass spectrometry (MS–MS) is a term which covers a number of techniques where one stage of mass spectrometry (not necessarily the first) is used to isolate an ion of interest and a second stage is then used to probe the relationship of this ion with others from which it may have been generated or which it may generate on decomposition. Chem 5570 Tandem Mass Spectrometry (MS–MS) Chem 5570 The two analyzers (MS-MS) can be separated by a collision cell (can be another MS) into which an inert gas (e.g. argon, xenon) is admitted to collide with the selected sample ions and bring about their fragmentation. Tandem MS have the ability to perform multiple steps on a single sample. The MS selects a specific ion, fragment the ion, and generate another mass spec – able to repeat the cycle several times. Chem 5570 The analyzers can be of the same or of different types, the most common combinations being: quadrupole - quadrupole magnetic sector - quadrupole magnetic sector - magnetic sector quadrupole - time-of-flight Fragmentation experiments can also be performed on certain single analyzer mass spectrometers such as ion trap and time-of-flight instruments, the latter type using a post-source decay experiment to effect the fragmentation of sample ions. Chem 5570 Tandem Mass Spectrometry (MS–MS) TIC - Total ion current or total ion chromatogram The TIC represents the sum of all signal intensities of a single scan spectrum. The TIC is usually calculated by the data system of the mass spectrometer and plotted against time or scan number to give a measure for evaporation/ionization of a sample over the duration of the whole measurement. -
Electrochemical Real-Time Mass Spectrometry: a Novel Tool for Time-Resolved Characterization of the Products of Electrochemical Reactions
Electrochemical real-time mass spectrometry: A novel tool for time-resolved characterization of the products of electrochemical reactions Elektrochemische Realzeit-Massenspektrometrie: Eine neuartige Methode zur zeitaufgelösten Charakterisierung der Produkte elektrochemischer Reaktionen Der Technischen Fakultät der Friedrich-Alexander-Universität Erlangen-Nürnberg zur Erlangung des Doktorgrades Dr.-Ingenieur vorgelegt von Peyman Khanipour Mehrin aus Shiraz, Iran Als Dissertation genehmigt von der Technischen Fakultät der Friedrich-Alexander-Universität Erlangen-Nürnberg Tag der mündlichen Prüfung: 17.11.2020 Vorsitzender des Promotionsorgans: Prof. Dr.-Ing. habil. Andreas Paul Fröba Gutachter: Prof. Dr. Karl J.J. Mayrhofer Prof. Dr. Frank-Michael Matysik I Acknowledgements This study is done in the electrosynthesis team of the electrocatalysis unit at Helmholtz- Institut Erlangen-Nürnberg (HI ERN) with the financial support of Forschungszentrum Jülich. I would like to express my deep gratitude to Prof. Dr. Karl J. J. Mayrhofer for accepting me as a Ph.D. student and also for all his encouragement, supports, and freedoms during my study. I’m grateful to Prof. Dr. Frank-Michael Matysik for kindly accepting to act as a second reviewer and also for the time he has invested in reading this thesis. This piece of work is enabled by collaboration with scientists from different expertise. I would like to express my appreciation to Dr. Sandra Haschke from FAU for providing shape-controlled high surface area platinum electrodes which I used for performing oxidation of primary alcohols and also the characterization of the provided material SEM, EDX, and XRD. Mr. Mario Löffler from HI ERN for obtaining the XPS data and his remarkable knowledge with the interpretation of the spectra on copper-based electrodes for the CO 2 electroreduction reaction. -
Front-End Methods for Enhancing the Analytical Power of Mass Spectrometry
FRONT-END METHODS FOR ENHANCING THE ANALYTICAL POWER OF MASS SPECTROMETRY PETER PAUL LIUNI A DISSERTAITON SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FUFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN CHEMISTRY YORK UNIVERSITY TORONTO, ONTARIO December 2015 © Peter Paul Liuni, 2015 Abstract The analytical power and versatility of mass spectrometry can be enhanced by adding ‘front-end’ devices, which provide additional functionality before, during or immediately after ElectroSpray Ionization (ESI). Such devices can include Ion mobility spectrometry (IMS) and Time-Resolved ElectroSpray Ionization (TRESI) which provide enhanced analysis of illicit compounds, protein folding, enzyme kinetics, and catalysis-linked dynamics. With respect to IMS, this work describes implementation of a hybrid Trace Compound Detector (TCD) system that combines IMS and MS to allow for rapid front- end mobility separation, followed by characterization and identification of analytical markers of seized opium by mass spectrometry. Ultimately, this device provides an avenue for rapid prosecution based on simultaneous detection and unambiguous identification of illicit drugs. TRESI is used to extend Mass Spectrometry (MS) to millisecond-timescale reaction studies. In the first instance, we combine TRESI with Travelling Wave Ion Mobility Spectrometry (TWIMS) to compare equilibrium and kinetic unfolding intermediates of cytochrome c, showing a high degree of correlation between all species populated under these substantially different regimes. We then combine TRESI with Hydrogen Deuterium Exchange (TRESI-HDX) to elucidate the relationship between structural fluctuations (conformational dynamics) of enzymes and their catalytic activity. The results of this work include a new model for catalysis-linked dynamics, in which the nature of the conformational landscape explored by an enzyme is independent of catalysis, but the rate at which the landscape is explored is enhanced for catalytically active species. -
In Ancient Egypt
THE ROLE OF THE CHANTRESS ($MW IN ANCIENT EGYPT SUZANNE LYNN ONSTINE A thesis submined in confonnity with the requirements for the degm of Ph.D. Graduate Department of Near and Middle Eastern Civiliations University of Toronto %) Copyright by Suzanne Lynn Onstine (200 1) . ~bsPdhorbasgmadr~ exclusive liceacc aiiowhg the ' Nationai hiof hada to reproduce, loan, distnia sdl copies of this thesis in miaof#m, pspa or elccmnic f-. L'atm criucrve la propri&C du droit d'autear qui protcge cette thtse. Ni la thèse Y des extraits substrrntiets deceMne&iveatetreimprimCs ouraitnmcrtrepoduitssanssoai aut&ntiom The Role of the Chmaes (fm~in Ancient Emt A doctorai dissertacion by Suzanne Lynn On*, submitted to the Department of Near and Middle Eastern Civilizations, University of Toronto, 200 1. The specitic nanire of the tiUe Wytor "cimûes", which occurrPd fcom the Middle Kingdom onwatd is imsiigated thrwgh the use of a dalabase cataloging 861 woinen whheld the title. Sorting the &ta based on a variety of delails has yielded pattern regatding their cbnological and demographical distribution. The changes in rhe social status and numbers of wbmen wbo bore the Weindicale that the Egyptians perceivecl the role and ams of the titk âiffefcntiy thugh tirne. Infomiation an the tities of ihe chantressw' family memkrs bas ailowed the author to make iderences cawming llse social status of the mmen who heu the title "chanms". MiMid Kingdom tifle-holders wverc of modest backgrounds and were quite rare. Eighteenth DMasty women were of the highest ranking families. The number of wamen who held the titk was also comparatively smaii, Nimeenth Dynasty women came [rom more modesi backgrounds and were more nwnennis. -
ADVANCED SPECTROMETER Introduction
ADVANCED SPECTROMETER Introduction In principle, a spectrometer is the simplest of scientific very sensitive detection and precise measurement, a real instruments. Bend a beam of light with a prism or diffraction spectrometer is a bit more complicated. As shown in Figure grating. If the beam is composed of more than one color of 1, a spectrometer consists of three basic components; a light, a spectrum is formed, since the various colors are collimator, a diffracting element, and a telescope. refracted or diffracted to different angles. Carefully measure The light to be analyzed enters the collimator through a the angle to which each color of light is bent. The result is a narrow slit positioned at the focal point of the collimator spectral "fingerprint," which carries a wealth of information lens. The light leaving the collimator is therefore a thin, about the substance from which the light emanates. parallel beam, which ensures that all the light from the slit In most cases, substances must be hot if they are to emit strikes the diffracting element at the same angle of inci- light. But a spectrometer can also be used to investigate cold dence. This is necessary if a sharp image is to be formed. substances. Pass white light, which contains all the colors of The diffracting element bends the beam of light. If the beam the visible spectrum, through a cool gas. The result is an is composed of many different colors, each color is dif- absorption spectrum. All the colors of the visible spectrum fracted to a different angle. are seen, except for certain colors that are absorbed by the gas. -
Comparison of the Characteristic Mass Fragmentations of Phenethylamines and Tryptamines by Electron Ionization Gas Chromatograph
applied sciences Article Comparison of the Characteristic Mass Fragmentations of Phenethylamines and Tryptamines by Electron Ionization Gas Chromatography Mass Spectrometry, Electrospray and Matrix-Assisted Laser Desorption Ionization Mass Spectrometry Bo-Hong Chen, Ju-Tsung Liu, Hung-Ming Chen, Wen-Xiong Chen and Cheng-Huang Lin * Department of Chemistry, National Taiwan Normal University, 88 Sec. 4 Tingchow Road, Taipei 11677, Taiwan; [email protected] (B.-H.C.); [email protected] (J.-T.L.); [email protected] (H.-M.C.); [email protected] (W.-X.C.) * Correspondence: [email protected]; Tel.: +886-2-7734-6170; Fax: +886-2-2932-4249 Received: 18 April 2018; Accepted: 19 June 2018; Published: 22 June 2018 Abstract: Characteristic mass fragmentation of 20 phenethylamine/tryptamine standards were investigated and compared by means of matrix assisted laser desorption/time-of-flight mass spectrometry (MALDI/TOFM), gas chromatography–electron ionization–mass spectrometry (GC-EI/MS) and liquid chromatography–electrospray ionization/mass spectrometry (LC-ESI/MS) + methods. As a result, three characteristic peaks ([M] and fragments from the Cβ-Cα bond breakage) were found to be unique and contained information useful in identifying 2C series compounds based on the GC-EI/MS method. We found that the protonated molecular ion ([M+H]+) and two types of fragments produced from the α-cleavage and β-cleavage processes were useful mass spectral information in the rapid screening and confirmation of phenethylamine and tryptamine derivatives when ESI/MS and MALDI/TOFMS methods were applied. This assay was successfully used to determine samples that contain illicit drugs. Keywords: phenethylamine; tryptamine; MALDI/TOFMS; GC-EI/MS; LC-ESI/MS 1. -
Spectrum 100 Series User's Guide
MOLECULAR SPECTROSCOPY SPECTRUM 100 SERIES User’s Guide 2 . Spectrum 100 Series User’s Guide Release History Part Number Release Publication Date L1050021 A October 2005 Any comments about the documentation for this product should be addressed to: User Assistance PerkinElmer Ltd Chalfont Road Seer Green Beaconsfield Bucks HP9 2FX United Kingdom Or emailed to: [email protected] Notices The information contained in this document is subject to change without notice. Except as specifically set forth in its terms and conditions of sale, PerkinElmer makes no warranty of any kind with regard to this document, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. PerkinElmer shall not be liable for errors contained herein for incidental consequential damages in connection with furnishing, performance or use of this material. Copyright Information This document contains proprietary information that is protected by copyright. All rights are reserved. No part of this publication may be reproduced in any form whatsoever or translated into any language without the prior, written permission of PerkinElmer, Inc. Copyright © 2005 PerkinElmer, Inc. Trademarks Registered names, trademarks, etc. used in this document, even when not specifically marked as such, are protected by law. PerkinElmer is a registered trademark of PerkinElmer, Inc. Spectrum, Spectrum 100, and Spectrum 100N are trademarks of PerkinElmer, Inc. Spectrum 100 Series User’s Guide . 3 Contents Contents............................................................................................... -
Coupling Gas Chromatography to Mass Spectrometry
Coupling Gas Chromatography to Mass Spectrometry Introduction The suite of gas chromatographic detectors includes (roughly in order from most common to the least): the flame ionization detector (FID), thermal conductivity detector (TCD or hot wire detector), electron capture detector (ECD), photoionization detector (PID), flame photometric detector (FPD), thermionic detector, and a few more unusual or VERY expensive choices like the atomic emission detector (AED) and the ozone- or fluorine-induce chemiluminescence detectors. All of these except the AED produce an electrical signal that varies with the amount of analyte exiting the chromatographic column. The AED does that AND yields the emission spectrum of selected elements in the analytes as well. Another GC detector that is also very expensive but very powerful is a scaled down version of the mass spectrometer. When coupled to a GC the detection system itself is often referred to as the mass selective detector or more simply the mass detector. This powerful analytical technique belongs to the class of hyphenated analytical instrumentation (since each part had a different beginning and can exist independently) and is called gas chromatograhy/mass spectrometry (GC/MS). Placed at the end of a capillary column in a manner similar to the other GC detectors, the mass detector is more complicated than, for instance, the FID because of the mass spectrometer's complex requirements for the process of creation, separation, and detection of gas phase ions. A capillary column is required in the chromatograph because the entire MS process must be carried out at very low pressures (~10-5 torr) and in order to meet this requirement a vacuum is maintained via constant pumping using a vacuum pump. -
Electron Ionization
Chapter 6 Chapter 6 Electron Ionization I. Introduction ......................................................................................................317 II. Ionization Process............................................................................................317 III. Strategy for Data Interpretation......................................................................321 1. Assumptions 2. The Ionization Process IV. Types of Fragmentation Pathways.................................................................328 1. Sigma-Bond Cleavage 2. Homolytic or Radical-Site-Driven Cleavage 3. Heterolytic or Charge-Site-Driven Cleavage 4. Rearrangements A. Hydrogen-Shift Rearrangements B. Hydride-Shift Rearrangements V. Representative Fragmentations (Spectra) of Classes of Compounds.......... 344 1. Hydrocarbons A. Saturated Hydrocarbons 1) Straight-Chain Hydrocarbons 2) Branched Hydrocarbons 3) Cyclic Hydrocarbons B. Unsaturated C. Aromatic 2. Alkyl Halides 3. Oxygen-Containing Compounds A. Aliphatic Alcohols B. Aliphatic Ethers C. Aromatic Alcohols D. Cyclic Ethers E. Ketones and Aldehydes F. Aliphatic Acids and Esters G. Aromatic Acids and Esters 4. Nitrogen-Containing Compounds A. Aliphatic Amines B. Aromatic Compounds Containing Atoms of Nitrogen C. Heterocyclic Nitrogen-Containing Compounds D. Nitro Compounds E. Concluding Remarks on the Mass Spectra of Nitrogen-Containing Compounds 5. Multiple Heteroatoms or Heteroatoms and a Double Bond 6. Trimethylsilyl Derivative 7. Determining the Location of Double Bonds VI. Library