Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2013)*
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Chapter 9 Titrimetric Methods 413
Chapter 9 Titrimetric Methods Chapter Overview Section 9A Overview of Titrimetry Section 9B Acid–Base Titrations Section 9C Complexation Titrations Section 9D Redox Titrations Section 9E Precipitation Titrations Section 9F Key Terms Section 9G Chapter Summary Section 9H Problems Section 9I Solutions to Practice Exercises Titrimetry, in which volume serves as the analytical signal, made its first appearance as an analytical method in the early eighteenth century. Titrimetric methods were not well received by the analytical chemists of that era because they could not duplicate the accuracy and precision of a gravimetric analysis. Not surprisingly, few standard texts from the 1700s and 1800s include titrimetric methods of analysis. Precipitation gravimetry developed as an analytical method without a general theory of precipitation. An empirical relationship between a precipitate’s mass and the mass of analyte— what analytical chemists call a gravimetric factor—was determined experimentally by taking a known mass of analyte through the procedure. Today, we recognize this as an early example of an external standardization. Gravimetric factors were not calculated using the stoichiometry of a precipitation reaction because chemical formulas and atomic weights were not yet available! Unlike gravimetry, the development and acceptance of titrimetry required a deeper understanding of stoichiometry, of thermodynamics, and of chemical equilibria. By the 1900s, the accuracy and precision of titrimetric methods were comparable to that of gravimetric methods, establishing titrimetry as an accepted analytical technique. 411 412 Analytical Chemistry 2.0 9A Overview of Titrimetry We are deliberately avoiding the term In titrimetry we add a reagent, called the titrant, to a solution contain- analyte at this point in our introduction ing another reagent, called the titrand, and allow them to react. -
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. -
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. -
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. -
Development of a Method for Xenon Determination in the Microstructure of High Burn-Up Nuclear Fuel
Diss. ETH No. 17527 Development of a Method for Xenon Determination in the Microstructure of High Burn-up Nuclear Fuel A dissertation submitted to the SWISS FEDERAL INSTITUTE OF TECHNOLOGY ZURICH for the degree of Dr. sc. ETH presented by MATTHIAS ISTVAN HORVATH Dipl. Phys. ETH born 24 August 1974 citizen of Châtillon (FR), Männedorf (ZH) - Switzerland citizen of Hungary accepted on the recommendation of Prof. Dr. D. Günther, examiner Prof. Dr. A. Wokaun, co-examiner Prof. Dr. Ch. Heinrich, co-examiner Dr. Ch. Hellwig, co-examiner 2008 II III Acknowledgements As many major work, this thesis could not have been performed and written, without the help and support of numerous people. This is especially true since this work was carried out at PSI and some experiments also at ETH combining different fields of research. I would like to send a special thank to my thesis advisor, Prof. Dr. Detlef Günther, and my supervisor Dr. Christian Hellwig for their support of my work at ETH and PSI. I am grateful to Dr. Marcel Guillong, with whom I got into the "world of LA-ICP-MS", and who’s experience was a great benefit. I would also to thank the members of the groups of Dr. Ines Günther-Leopold (Isotope and Element Analysis), Dr. Didier Gavillet (Surface and Solid State Materials), Daniel Kuster (Hot Cell Experiments), Dr. Johannes Bertsch (Core Safety Material Behavior) at PSI, and the trace element group of Prof. Dr. Detlef Günther at ETH. Without their support and the possibility using their infrastructure, this thesis could not be realized. -
Fundamental Understanding of Chemical Processes in Extreme Ultraviolet Resist Materials
Lawrence Berkeley National Laboratory Recent Work Title Fundamental understanding of chemical processes in extreme ultraviolet resist materials. Permalink https://escholarship.org/uc/item/50h4g627 Journal The Journal of chemical physics, 149(15) ISSN 0021-9606 Authors Kostko, Oleg Xu, Bo Ahmed, Musahid et al. Publication Date 2018-10-01 DOI 10.1063/1.5046521 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Fundamental understanding of chemical processes in extreme ultraviolet resist materials Oleg Kostko,1 Bo Xu,1 Musahid Ahmed,1 Daniel S. Slaughter,1 D. Frank Ogletree,2 Kristina D. Closser,2 David G. Prendergast,2 Patrick Naulleau,3 Deirdre L. Olynick,2 Paul D. Ashby,2 Yi Liu,2 William D. Hinsberg,4 Gregory M. Wallraff5 1Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA 2Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA 3Center for X‐Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, CA, USA 4Columbia Hill Technical Consulting, Fremont, CA, USA 5IBM, Almaden, CA, USA ABSTRACT New photoresists are needed to advance extreme ultraviolet (EUV) lithography. Tailored design of efficient photoresists is enabled by a fundamental understanding of EUV induced chemistry. Processes that occur in the resist film after absorption of an EUV photon are discussed and a novel approach to study these processes on a fundamental level is described. The processes of photoabsorption, electron emission, and molecular fragmentation were studied experimentally in the gas‐phase on analogues of the monomer units employed in chemically amplified EUV resists. To demonstrate the dependence of the EUV absorption cross‐section on selective light harvesting substituents, halogenated methylpenols were characterized employing the following techniques. -
Analytical Chemistry Laboratory Manual 2
ANALYTICAL CHEMISTRY LABORATORY MANUAL 2 Ankara University Faculty of Pharmacy Department of Analytical Chemistry Analytical Chemistry Practices Contents INTRODUCTION TO QUANTITATIVE ANALYSIS ......................................................................... 2 VOLUMETRIC ANALYSIS .............................................................................................................. 2 Volumetric Analysis Calculations ................................................................................................... 3 Dilution Factor ................................................................................................................................ 4 Standard Solutions ........................................................................................................................... 5 Primary standard .............................................................................................................................. 5 Characteristics of Quantitative Reaction ......................................................................................... 5 Preparation of 1 L 0.1 M HCl Solution ........................................................................................... 6 Preparation of 1 L 0.1 M NaOH Solution ....................................................................................... 6 NEUTRALIZATION TITRATIONS ...................................................................................................... 7 STANDARDIZATION OF 0.1 N NaOH SOLUTION ...................................................................... -
Structural Amd Analytical Studies by Tandem Mass Spectrometry
STRUCTURAL AMD ANALYTICAL STUDIES BY TANDEM MASS SPECTROMETRY A Thesis submitted by TRACEY MADDEN for the degree of Doctor of Philosophy in the University of London Faculty of Science Department of Pharmaceutical Chemistry The School of Pharmacy University of London ProQuest Number: U556261 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest U556261 Published by ProQuest LLC(2017). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C ode Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 CONTENTS CHAPTER 1: INTRODUCTION 1.1 Tandem Mass Spectrometry ................... 1 REFERENCES ................................. 4 CHAPTER 2: THEORY 2.1 Mass Spectrometry ......................... 5 2.2 Formation of the Molecular Ion ............ 8 2.2.1 Vertical and Adiabatic Ionisation Potentials ......................... 9 2.2.2 Ionisation Efficiency Curve .......... 9 2.2.3 Appearance Energy ................... 10 2.3 Quasi Equilibrium Theory ................. 14 2.4 Fragmentation ............................ 16 2.4.1 Stevenson's Rule .................... 17 2.5 Rearrangement ............................ 19 2.6 Ion Stability ............................ 20 2.6.1 Stable Ions ......................... 20 2.6.2 Unstable Ions ....................... 21 2.6.3 Metastable Ions ..................... 21 2.6.3.1 Kinetic Energy Release ......... 22 2.6.3.2 Metastable Peak Shapes ....... -
Analytical Chemistry in the 21St Century: Challenges, Solutions, and Future Perspectives of Complex Matrices Quantitative Analyses in Biological/Clinical Field
Review Analytical Chemistry in the 21st Century: Challenges, Solutions, and Future Perspectives of Complex Matrices Quantitative Analyses in Biological/Clinical Field 1, 2, 2, 3 Giuseppe Maria Merone y, Angela Tartaglia y, Marcello Locatelli * , Cristian D’Ovidio , Enrica Rosato 3, Ugo de Grazia 4 , Francesco Santavenere 5, Sandra Rossi 5 and Fabio Savini 5 1 Department of Neuroscience, Imaging and Clinical Sciences, University of Chieti–Pescara “G. d’Annunzio”, Via dei Vestini 31, 66100 Chieti, Italy; [email protected] 2 Department of Pharmacy, University of Chieti-Pescara “G. d’Annunzio”, Via Dei Vestini 31, 66100 Chieti (CH), Italy; [email protected] 3 Section of Legal Medicine, Department of Medicine and Aging Sciences, University of Chieti–Pescara “G. d’Annunzio”, 66100 Chieti, Italy; [email protected] (C.D.); [email protected] (E.R.) 4 Laboratory of Neurological Biochemistry and Neuropharmacology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Via Celoria 11, 20133 Milano, Italy; [email protected] 5 Pharmatoxicology Laboratory—Hospital “Santo Spirito”, Via Fonte Romana 8, 65124 Pescara, Italy; [email protected] (F.S.); [email protected] (S.R.); [email protected] (F.S.) * Correspondence: [email protected]; Tel.: +39-0871-3554590; Fax: +39-0871-3554911 These authors contributed equally to the work. y Received: 16 September 2020; Accepted: 16 October 2020; Published: 30 October 2020 Abstract: Nowadays, the challenges in analytical chemistry, and mostly in quantitative analysis, include the development and validation of new materials, strategies and procedures to meet the growing need for rapid, sensitive, selective and green methods. -
The Air Oxidation of 4,6-Di (2-Phenyl-2-Propyl) Pyrogallol. Spectroscopic and Kinetic Studies of the Intermediates
Carlsberg Res. Commun. Vol. 42, p. 11-25 THE AIR OXIDATION OF 4,6-DI (2-PHENYL-2-PROPYL) PYROGALLOL. SPECTROSCOPIC AND KINETIC STUDIES OF THE INTERMEDIATES. by HENRY I. ABRASH Department of Chemistry, Carlsberg Laboratory Gamle Carlsbergvej 10 - DK-2500 Copenhagen, Valby~ 1) Current address: Department of Chemistry, California State University at Northridge, Northridge, California 91324, USA Key words: 4,6-di (2-phenyl-2-propyl) pyrogallol, consecutive reactions, oxidation, oxygen, pH, quinone, semiquinone, spectra Two colored extinction bands, one with ~'max near 520 nm and the other near 770 nm, form and decay during air oxidations of 4,6-di(2-phenyl-2-propyl)pyrogallol in alkaline methanol. The 770 nm band appears to be due to the semiquinone monoanion while the extinction near 500 nm is thought to be due to both the semiquinone and 3-hydroxy-o-quinone. Although the rates of formation and decay of the two bands are indistinguishable in the presence of excess dissolved oxygen, the 770 nm band disappears slightly before the 500 nm extinction when the pyrogallol reactant is initially in excess of the dissolved oxygen. Except at high methoxide concentrations, the kinetics indicate a system of two consecutive reactions with pseudo first-order rate constants k~ and k 2. The pH' dependence of k~ indicates that the neutral pyrogallol, its monoanion and dianion all react, the rate increasing with the negative charge of the species. The k2/k~ ratio is constant at 5 from pH' 11 to 16. Extinction coefficients at both wavelengths increase with pH'. The 770 nm extinction disappears immediately after acidification while the 500 nm extinction decays at a rate consistent with oxidation. -
Solvent Deuterium Isotope Effect on Hydrolysis of Nd3+ Ion , and As Was
Notizen 1493 Solvent Deuterium Isotope Effect on Hydrolysis Experimental of Nd3+ Ion Reagents and apparatus A neodymium perchlorate sample solution and Mastjnobu Ma e d a *, T oshihiko A m ay a , and other reagents used were prepared and analyzed H id e t a k e K ak iha na according to the same procedures as those in the *Department of Applid Chemistry, previous papers5-6. Nagoya Institute of Technology, All the apparatus employed were the same as Gokiso, Showa-ku, Nagoya 466, Japan those in Ref. 7. Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Preparation of a test solution O-okayama, Meguro-ku, Tokyo 152, Japan A test solution was prepared as follows. A (Z. Naturforsch. 32 b, 1493-1495 [1977]; received August 30, 1977) slightly acidic neodymium perchlorate solution, which had been freed from CO 2 by passing purified Deuterium Isotope Effect, Formation Constant, Heavy Water, Hydrolysis, Neodymium Ion N2 gas, was electrolyzed to reduce L+ ions by using a d. c. power supply until precipitates appeared. In order to saturate the solution with Nd(OL )3 precipi The hydrolysis equilibria of Nd3+ ion in tates the mixture was stirred with a magnetic rod light- and heavy-water solutions containing for two days. The precipitates of Nd(OL )3 were 3 mol dm -3 (Li)C104 as an ionic medium were removed by filtration with G 4 glass filters. All the studied at 25 °C by measuring the lyonium- procedures were carried out under an atmosphere ion concentration with a glass electrode. of N 2 gas in a room kept at 25 ± 1 °C.