DOCSLIB.ORG

Fundamentals of Ambient Metastable-Induced Chemical Ionization Mass Spectrometry and Atmospheric Pressure Ion Mobility Spectrometry

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Fundamentals of Ambient Metastable-Induced Chemical Ionization Mass Spectrometry and Atmospheric Pressure Ion Mobility Spectrometry FUNDAMENTALS OF AMBIENT METASTABLE-INDUCED CHEMICAL IONIZATION MASS SPECTROMETRY AND ATMOSPHERIC PRESSURE ION MOBILITY SPECTROMETRY A Dissertation Presented to The Academic Faculty by Glenn A. Harris In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Chemistry & Biochemistry Georgia Institute of Technology August 2011 FUNDAMENTALS OF AMBIENT METASTABLE-INDUCED CHEMICAL IONIZATION MASS SPECTROMETRY AND ATMOSPHERIC PRESSURE ION MOBILITY SPECTROMETRY Approved by: Dr. Facundo M. Fernández, Advisor Dr. M. Cameron Sullards School of Chemistry & Biochemistry School of Chemistry & Biochemistry Georgia Institute of Technology Georgia Institute of Technology Dr. Thomas M. Orlando Dr. Greg Huey School of Chemistry & Biochemistry School of Earth and Atmospheric Georgia Institute of Technology Sciences Georgia Institute of Technology Dr. Lawrence Bottomley School of Chemistry & Biochemistry Georgia Institute of Technology Date Approved: May 26th, 2011 Harris, G. A. ii I’m smart enough to know that I’m dumb. — Richard Feynman This is dedicated to… my parents, Martin and Mary Ann Harris, for advice beyond description, teaching me how to work hard and reminding me to enjoy the ride, my brother, Craig M. Harris, for being a great role model and friend, and my grandma, Mary Quattrocki, for always being supportive. To those listed above, and the rest of my family and friends, thank you for your unconditional love and support. ACKNOWLEDGEMENTS First I would like to express my gratitude to my advisor, Dr. Facundo M. Fernández, for guidance and support during the past four years. Under your supervision, my training and growth as a scientist has been outstanding. I am grateful for the financial and professional support needed to pursue the work outlined in this dissertation. I look forward to many years of friendship and collaboration. In addition, I would like to thank my committee members Dr. Thomas M. Orlando, Dr. Lawrence Bottomley, Dr. M. Cameron Sullards and Dr. Greg Huey for their advisement and interest in my graduate research. My fellow group members deserve significant thanks. Our past group members, Dr. Christina Y. Hampton, Dr. Leonard Nyadong, Dr. Arti Navare, Dr. Mark Kwasnik and Dr. Carrie Pierce set the expectations high upon my arrival. Current group members including Jose Perez, Christina Jones, Dana Hostetler, Deanna Synder, Rachel Bennett, Joel Keelor and my undergraduate researcher Caitlin E. Falcone, provided the day-to-day assistance required for the completion of my work. Also, I would like to thank Dr. Asiri S. Galhena and Dr. Manshui Zhou for their research insight as excellent post doctoral and research scientist colleagues. My collaborators and funding agencies have provided invaluable help for many of the projects I pursued. Special thanks is given to Dr. David Powell, Dr. Gary Eiceman, Dr. Jennifer Brodbelt, Dr. Douglas Henderson and Northrop Grumman, Dr. Joe Chipuk and Signature Science, Dr. Katrin Fuhrer, Dr. Marc Gonin and Dr. Richard Knochenmuss at Tofwerk AG, Dr. Michael Greene, Dr. Paul Newton, the National Science Foundation and the Department of Homeland Security. I am also grateful for the services of Sam Harris, G. A. v Mize at the College of Science machine shop as well as Richard Berdell and Jose Fonts in the School of Chemistry and Biochemistry electronics shop. I have been lucky to have many friends while studying at Georgia Tech. I must thank Michael and Sarah Stollar Smith for being a never ending source of fun, excitement and memories. Please give Betty a belly rub and a few treats for me when I leave. My roommate and friend, Nick Haase, has been a great research colleague and fellow concert and fine-dining companion while in Atlanta. I am sure Nick’s cat Sherman will enjoy life more without my constant pestering. My coffee breaks and late night adventures will never be the same without Susan Orwig. I wish you and your family my best. Other friends here in Atlanta (Jessica Peters, Lauren-Christine Orwig, Craig Clark, James Goeders, William “Chip” Humphries IV, Anthony Baldrige, Nicole Marrotta, and Meg Mackey) and old friends (Dane Lewis, Pierce Wolfinbarger, Dr. Diana Tadros, Julia Shaw, Dr. Anne Shearrow and Erica Turner) should also be thanked for their humor and support over the years. Finally and most importantly, I would like to thank my family for their unconditional love. To my parents, Martin and Mary Ann Harris, you have raised two sons better than any parents could wish for. This degree is as much yours as it is mine. Thank you for your patience, and I promise to get a real job someday. To my brother, Craig M. Harris, who would have thought that I would be the scientist in the family and you the lawyer? I look forward to your wedding later this year with M. Ashley Cain, seeing Kosmo and Clarence (the dogs) and spending many more fun weekend trips with you. Also, thank you to the rest of my family. Without you all, this task would not be possible. Harris, G. A. vi TABLE OF CONTENTS ACKNOWLEDGEMENTS………………………………………………………... v LIST OF TABLES………………………………………………………………..... xiii LIST OF FIGURES………………………………………………………………... xiv LIST OF SCHEMES………………………………………………………………. xxi LIST OF SYMBOLS……………………………………………………………..... xxii LIST OF ABBREVIATIONS……………………………………………………... xxiii SUMMARY……………………………………………………………………….... xxvi CHAPTER 1. RECENT DEVELOPMENTS WITH AMBIENT MASS SPECTROMETRY……………………………………….... 1 1.1. Abstract………………………………………………………………. ....1 1.2. Emerging Ionization Techniques: An Introduction to Ambient MS….... 1 1.3. Overview of Plasma-Based Techniques………………………………... 3 1.4. Direct Analysis In Real Time (DART)……………………………….... 5 1.4.1. Fundamentals……………………………………………….... 5 1.4.2. Instrumentation……………………………………………..... 11 1.4.3. Applications………………………………………………….. 14 1.5. Conclusion……………………………………………………………... 25 CHAPTER 2. Simulations and Experimental Investigation of Atmospheric Transport In an Ambient Metastable-Induced Chemical Ionization Source………………………………………………………………….. 26 2.1. Abstract………………………………………………………………... 26 2.2. An Introduction to Direct Analysis In Real Time………………….…. 26 2.2.1. Physicochemical Properties of DART…………………….... 26 Harris, G. A. vii 2.3. Experimental…………………………………………………………... 28 2.3.1. Instrumentation…………………………………………….... 28 2.3.2. Computer Simulations……………………………………..... 30 2.3.3. Procedure……………………………………………………. 31 2.4. Finite Element Analysis of the Ionization Source…………………….. 32 2.5. Combined Fluid-Thermal Dynamic and Electrostatic Simulations With Experimental Validation of the Spatial Variations Within The DART Ionization Region…………………………………………. 34 2.6. The Role of Sample Geometry In Space On the Observed Experimental Sensitivities With DART……………………………….. 45 2.7. Conclusion……………………………………………………………... 49 CHAPTER 3. Comparison of the Internal Energy Deposition of Direct Analysis In Real Time and Electrospray Ionization Time-of-Flight Mass Spectrometry………………………………………………………………... 50 3.1. Abstract………………………………………………………………... 50 3.2. Internal Energy Deposition……………………………………………. 50 3.2.1. Internal Energy Deposition During Ionization………………. 50 3.3. Experimental Determination of the Internal Energy Deposition…….... 52 3.3.1. Synthesis and Preparation of Para-Substituted Benzylpyridinium Salts……………………………………... 52 3.3.2. DART-MS Sampling, Instrumentation and Data Acquisition…………………………………………………... 53 3.3.3. ESI-MS Experiments, Instrumentation and Data Acquisition…………………………………………………... 55 3.3.4. Survival Yield Method and Data Analysis………………...... 56 3.3.5. Computational Fluid Dynamic Simulations……………….... 58 3.4. Determination of the Internal Energy Deposition of DART Harris, G. A. viii Compared to ESI…………………………………………………….... 59 3.5. Thermal Activation Pathways of Internal Energy Deposition………... 62 3.6. Collisional Activation Effects of Internal Energy Deposition………... 67 3.7. Influence of Fluid Dynamics on Internal Energy Deposition……….... 68 3.8. Metastable-Stimulated Desorption Effects on Internal Energy Deposition……………………………………………………………... 69 3.9. Conclusion…………………………………………………………….. 70 CHAPTER 4. Ion Yield “Hot Spots” and Suppression Effects In Direct Analysis In Real Time Mass Spectrometry of Nerve Agent Simulants……….. 71 4.1. Abstract………………………………………………………………... 71 4.2. Physicochemical Effects In the DART Ionization Region……………. 72 4.3. Experimental Set-Up of Continuous DART Sampling……………….. 73 4.3.1. Chemicals and Gases………………………………………... 73 4.3.2. DART-MS Instrumentation…………………………………. 73 4.3.3. DART-MS of Continuous Liquid Samples…………………. 74 4.4. Sampling Region Temperature Gradients…………………………….. 76 4.5. Spatial Sensitivity and Dynamic Range………………………………. 79 4.6. Ion Suppression……………………………………………………….. 84 4.7. Conclusion…………………………………………………………….. 92 CHAPTER 5. Direct Analysis In Real Time Coupled To Multiplexed Drift Tube Ion Mobility Spectrometry……………………………………………….... 94 5.1. Abstract………………………………………………………………... 94 5.2. Chemical Detection Systems………………………………………….. 94 5.2.1. Recent Developments With Chemical Detection Platforms... 94 5.2.2. Ionization Techniques Used With Drift Tube Ion Mobility Harris, G. A. ix Spectrometry……………………………………………….... 95 5.3. Experimental Development of the DART-DTIMS Platform………….. 96 5.3.1. Drift Tube Ion Mobility Spectrometer and DART Instrumentation Setup………………………………………... 96 5.3.2. DART-IMS Sample Analysis………………………………... 98 5.3.3. Determination of Reduced Mobility Terms………………….. 100 5.4. Initial Assessment of DART-DTIMS Platform………………………... 101 5.5. Probability of Detection of Toxic Industrial Chemicals……………….
Load more

Recommended publications
  • Effect of Diethylenetriamine and Triethylamine Sensitization on the Critical Diameter of Nitromethane’
    CP505, Shock Compression of Condensed Matter - 1999 edited by M. D. Furnish, L. C. Chhabildas, and R. S. Hixson 0 2000 American Institute of Physics l-56396-923-8/00/$17.00 EFFECT OF DIETHYLENETRIAMINE AND TRIETHYLAMINE SENSITIZATION ON THE CRITICAL DIAMETER OF NITROMETHANE’ J.J. Lee*, J. Jiang?, K.H. Choong’, J.H.S. Lee’ *Graduate Aeronautics Laboratory, California Institute of Technology, Pasadena, CA 9112.5, USA ‘Dept. of Mechanical Engineering, McGill University, Montr&al, Que’bec, Canada, H3A 2K6 In this work, the critical diameter for detonation was measured for Nitromethane (NM) sensitized with two different amines: Diethylenetriamine (DETA) and Triethylamine (TEA). The critical diameter in glass and polyvinylchloride tubes is found to decrease rapidly as the amount of sensitizer is increased, then increase past a critical amount of sensitizer. Thus the critical diameter reaches a minimum at a critical concentration of sensitizer. It was also found that the critical diameter is lower with DETA than with TEA. INTRODUCTION propagation in various tubes and channels, and the critical conditions for propagation in porous media Previous studies have shown that small (3) . concentrations of certain substances can strongly The effect of DETA on the critical diameter of increase the explosive sensitivity nitromethane NM has been reported by Engelke (4), who (NM). Amines are found to be the most effective performed measurements with up to 2.5% DETA by chemical sensitizing agent for NM with mass in NM. Engelke observed a reduction in the ethylenediamine and diethylenetriamine (DETA) critical diameter of over 50% in the range of DETA producing the largest increase in the card gap value concentrations used.
    [Show full text]
  • Trihalomethanes/MTBE/Nitromethane Lab Procedure Manual
    Laboratory Procedure Manual Analyte: Trihalomethanes/MTBE/Nitromethane Matrix: Whole Blood Method: Solid Phase Microextraction with GC Separation/High Resolution MS Method No: 2101.01 Revised: April 30, 2015 As performed by: Tobacco & Volatiles Branch Division of Laboratory Sciences National Center for Environmental Health Contact: Dr. Ben Blount Phone: 770-488-7894 Fax: 770-488-0181 Email: [email protected] James L. Pirkle, M.D., Ph.D. Director, Division of Laboratory Sciences Important Information for Users The Centers for Disease Control and Prevention (CDC) periodically refines these laboratory methods. It is the responsibility of the user to contact the person listed on the title page of each write-up before using the analytical method to find out whether any changes have been made and what revisions, if any, have been incorporated. THMs & MTBE VOCs in Blood DLS Method Code: 2101.01 National Center for Health Staistics 2 This document details the Lab Protocol for testing the items listed in the following table Data File Name Variable Name SAS Label LBXVBF Blood Bromoform (pg/mL) LBXVBM Blood Bromodichloromethane (pg/mL) VOCMWB_F LBXVCF Blood Chloroform (pg/mL) LBXVCM Blood Dibromochloromethane (pg/mL) LBXVME Blood MTBE (pg/mL) LBXVNM Blood Nitromethane (pg/mL) THMs & MTBE VOCs in Blood DLS Method Code: 2101.01 National Center for Health Staistics 3 1. Clinical Relevance and Summary of Test Principle a. Clinical Relevance The prevalence of disinfection by-products in drinking water supplies has raised concerns about possible adverse health effects from chronic exposure to these potentially carcinogenic compounds. To support studies exploring the relation between exposure to trihalomethanes (THMs), nitromethane (NM: biomarker for halonitromethanes), methyl tert-butyl ether (MTBE) and adverse health effects, an automated analytical method was developed using capillary gas chromatography (GC) and high-resolution mass spectrometry (MS) with selected ion mass detection and isotope-dilution techniques.
    [Show full text]
  • Contents • Introduction to Proteomics and Mass Spectrometry
    Contents • Introduction to Proteomics and Mass spectrometry - What we need to know in our quest to explain life - Fundamental things you need to know about mass spectrometry • Interfaces and ion sources - Electrospray ionization (ESI) - conventional and nanospray - Heated nebulizer atmospheric pressure chemical ionization - Matrix assisted laser desorption • Types of MS analyzers - Magnetic sector - Quadrupole - Time-of-flight - Hybrid - Ion trap In the next step in our quest to explain what is life The human genome project has largely been completed and many other genomes are surrendering to the gene sequencers. However, all this knowledge does not give us the information that is needed to explain how living cells work. To do that, we need to study proteins. In 2002, mass spectrometry has developed to the point where it has the capacity to obtain the "exact" molecular weight of many macromolecules. At the present time, this includes proteins up to 150,000 Da. Proteins of higher molecular weights (up to 500,000 Da) can also be studied by mass spectrometry, but with less accuracy. The paradigm for sequencing of peptides and identification of proteins has changed – because of the availability of the human genome database, peptides can be identified merely by their masses or by partial sequence information, often in minutes, not hours. This new capacity is shifting the emphasis of biomedical research back to the functional aspects of cell biochemistry, the expression of particular sets of genes and their gene products, the proteins of the cell. These are the new goals of the biological scientist: o to know which proteins are expressed in each cell, preferably one cell at a time o to know how these proteins are modified, information that cannot necessarily be deduced from the nucleotide sequence of individual genes.
    [Show full text]
  • Acute Tetraethyllead Poisoning
    Arch. Toxikol. 24, 283--291 (1969) Acute Tetraethyllead Poisoning M. STASIK, Z. BYCZKOWSKA, S. SZENDZIKOWSKI,and Z. FIEDOttCZUK Clinical and Pathomorphological Department, Institute of Occupational Medicine, L6@, Poland, Department of Forensic Medicine, Medical Academy, L6dA l%eceived September 16, 1968 Summary. Four cases of accidental poisoning with tetraethyllead are described. Three out of four of the patients died. In the first case, pure ethyl fluid was accidentally ingested. Dominating the clinical picture of this patient were signs of greatly elevated intracranial pressure. Three other persons were poisoned as a group. They unknowingly inhaled tetra- ethyllead contained in a paint solvent they used. In these three cases, the intoxication manifested itself predominantly as a mental disorder suggestive of schizophrenia. Gross and microscopic changes observed in the fatal cases gave evidence of a capillary vascular lesion, particularly involving the vessels of the CNS. Liver damage and less severe damage to the heart muscle and kidney parenchyma were also noted. The distribution as well as the extent of the above mentioned lesions correlate approximately with the distribution and concentration of triethyllead in the various internal organs. Key- Words: Tetraethyllead -- Mental Disorder -- Damage to Parenchymatous Organs. Zusammen/assung. Die Verfasser berichten fiber 4 F/ille, yon denen 3 tSdlich waren, zuf~lliger Vergiftungen durch das sog. Ethylfluid, das Bleitetra~thyl enthElt. Im ersten Fall trat die t6dliche Vergiftung infolge irrtfimlich getrunkenem Ethylfluid auf. Als klinisches Symptom entstand erh6hter intrakranieller Druck. In den drei n~ehsten F~llen besa6 die Vergiftung einen kollektiven Charakter und war durch den Respirationstrakt zustande gekommen; zwei von den Vergifteten sind gestorben.
    [Show full text]
  • Mass Spectrometry (Technically Not Spectroscopy)
    Mass Spectrometry (technically not Spectroscopy) So far, In mass spec, on y Populati Intensit Excitation Energy “mass” (or mass/charge ratio) Spectroscopy is about Mass spectrometry interaction of energy with matter. measures population of ions X-axis is real. with particular mass. General Characteristics of Mass Spectrometry 2. Ionization Different variants of 1-4 -e- available commercially. 4. Ion detection 1. Introduction of sample to gas phase (sometimes w/ separation) 3. Selection of one ion mass (Selection nearly always based on different flight of ion though vacuum.) General Components of a Mass Spectrometer Lots of choices, which can be mixed and matched. direct injection The Mass Spectrum fragment “daughter” ions M+ “parent” mass Sample Introduction: Direc t Inser tion Prob e If sample is a liquid, sample can also be injected directly into ionization region. If sample isn’t pure, get multiple parents (that can’t be distinguished from fragments). Capillary Column Introduction Continous source of molecules to spectrometer. detector column (including GC, LC, chiral, size exclusion) • Signal intensity depends on both amount of molecule and ionization efficiency • To use quantitatively, must calibrate peaks with respect eltilution time ttlitotal ion curren t to quantity eluted (TIC) over time Capillary Column Introduction Easy to interface with gas or liquid chromatography. TIC trace elution time time averaged time averaged mass spectrum mass spectrum Methods of Ionization: Electron Ionization (EI) 1 - + - 1 M + e (kV energy) M + 2e Fragmentation in Electron Ionization daughter ion (observed in spectrum) neutral fragment (not observed) excited parent at electron at electron energy of energy of 15 eV 70 e V Lower electron energy yields less fragmentation, but also less signal.
    [Show full text]
  • An Introduction to Mass Spectrometry
    An Introduction to Mass Spectrometry by Scott E. Van Bramer Widener University Department of Chemistry One University Place Chester, PA 19013 [email protected] http://science.widener.edu/~svanbram revised: September 2, 1998 © Copyright 1997 TABLE OF CONTENTS INTRODUCTION ........................................................... 4 SAMPLE INTRODUCTION ....................................................5 Direct Vapor Inlet .......................................................5 Gas Chromatography.....................................................5 Liquid Chromatography...................................................6 Direct Insertion Probe ....................................................6 Direct Ionization of Sample ................................................6 IONIZATION TECHNIQUES...................................................6 Electron Ionization .......................................................7 Chemical Ionization ..................................................... 9 Fast Atom Bombardment and Secondary Ion Mass Spectrometry .................10 Atmospheric Pressure Ionization and Electrospray Ionization ....................11 Matrix Assisted Laser Desorption/Ionization ................................ 13 Other Ionization Methods ................................................13 Self-Test #1 ...........................................................14 MASS ANALYZERS .........................................................14 Quadrupole ............................................................15
    [Show full text]
  • FIA Technical Regulations for Drag Racing
    FIA DRAG RACING SECTION 1 - JUNIOR DRAGSTER & JUNIOR FUNNY CAR 2021 Specific Regulations for FIA Drag Racing These Technical Regulations provide guidelines and minimum standards for the construction and operation of vehicles used in FIA Drag Racing. It is the responsibility of the participant to be familiar with the contents of these Technical Regulations and to comply with its requirements. It is not the responsibility of the officials to discover all potential rule compliance issues. The responsibility for compliance with these Technical Regulations rests first and foremost with the competitor. Additional safety equipment or safety-enhancing equipment is always permitted and the levels of safety equipment stated in these Technical Regulations are minimum prescribed levels for a particular type of competition and do not prohibit the individual competitor from using additional safety equipment. Competitors are encouraged to investigate the availability of additional safety devices or equipment for their type of competition. In disputed cases, whether an item, device or piece of equipment is safety-enhancing or performance-enhancing will be determined by the FIA Technical Delegate or the FIA Technical Department. Furthermore, as to performance-enhancing equipment, it is the general principle that unless optional performance-enhancing equipment or performance- related modifications are specifically permitted by these Technical Regulations, they are prohibited. Throughout these Technical Regulations, a number of references are made for particular products and equipment to meet certain standards and specifications (i.e. FIA-Standard, SFI Specs, Snell, DOT, etc.). It is important to realize that these products are manufactured to meet certainspecifications, and upon completion, the manufacturer labels the product as meeting that standard or specification.
    [Show full text]
  • NMR Chemical Shifts of Common Laboratory Solvents As Trace Impurities
    7512 J. Org. Chem. 1997, 62, 7512-7515 NMR Chemical Shifts of Common Laboratory Solvents as Trace Impurities Hugo E. Gottlieb,* Vadim Kotlyar, and Abraham Nudelman* Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel Received June 27, 1997 In the course of the routine use of NMR as an aid for organic chemistry, a day-to-day problem is the identifica- tion of signals deriving from common contaminants (water, solvents, stabilizers, oils) in less-than-analyti- cally-pure samples. This data may be available in the literature, but the time involved in searching for it may be considerable. Another issue is the concentration dependence of chemical shifts (especially 1H); results obtained two or three decades ago usually refer to much Figure 1. Chemical shift of HDO as a function of tempera- more concentrated samples, and run at lower magnetic ture. fields, than today’s practice. 1 13 We therefore decided to collect H and C chemical dependent (vide infra). Also, any potential hydrogen- shifts of what are, in our experience, the most popular bond acceptor will tend to shift the water signal down- “extra peaks” in a variety of commonly used NMR field; this is particularly true for nonpolar solvents. In solvents, in the hope that this will be of assistance to contrast, in e.g. DMSO the water is already strongly the practicing chemist. hydrogen-bonded to the solvent, and solutes have only a negligible effect on its chemical shift. This is also true Experimental Section for D2O; the chemical shift of the residual HDO is very NMR spectra were taken in a Bruker DPX-300 instrument temperature-dependent (vide infra) but, maybe counter- (300.1 and 75.5 MHz for 1H and 13C, respectively).
    [Show full text]
  • Methods of Ion Generation
    Chem. Rev. 2001, 101, 361−375 361 Methods of Ion Generation Marvin L. Vestal PE Biosystems, Framingham, Massachusetts 01701 Received May 24, 2000 Contents I. Introduction 361 II. Atomic Ions 362 A. Thermal Ionization 362 B. Spark Source 362 C. Plasma Sources 362 D. Glow Discharge 362 E. Inductively Coupled Plasma (ICP) 363 III. Molecular Ions from Volatile Samples. 364 A. Electron Ionization (EI) 364 B. Chemical Ionization (CI) 365 C. Photoionization (PI) 367 D. Field Ionization (FI) 367 IV. Molecular Ions from Nonvolatile Samples 367 Marvin L. Vestal received his B.S. and M.S. degrees, 1958 and 1960, A. Spray Techniques 367 respectively, in Engineering Sciences from Purdue Univesity, Layfayette, IN. In 1975 he received his Ph.D. degree in Chemical Physics from the B. Electrospray 367 University of Utah, Salt Lake City. From 1958 to 1960 he was a Scientist C. Desorption from Surfaces 369 at Johnston Laboratories, Inc., in Layfayette, IN. From 1960 to 1967 he D. High-Energy Particle Impact 369 became Senior Scientist at Johnston Laboratories, Inc., in Baltimore, MD. E. Low-Energy Particle Impact 370 From 1960 to 1962 he was a Graduate Student in the Department of Physics at John Hopkins University. From 1967 to 1970 he was Vice F. Low-Energy Impact with Liquid Surfaces 371 President at Scientific Research Instruments, Corp. in Baltimore, MD. From G. Flow FAB 371 1970 to 1975 he was a Graduate Student and Research Instructor at the H. Laser Ionization−MALDI 371 University of Utah, Salt Lake City. From 1976 to 1981 he became I.
    [Show full text]
  • Technical Note TN-106 a Guideline for PID Instriment Response
    Technical Note TN-106 05/15/VK A GUIDELINE FOR PID INSTRUMENT RESPONSE CORRECTION FACTORS AND IONIZATION ENERGIES* Example 1: RAE Systems PIDs can be used for the detection of a wide variety of With the unit calibrated to read isobutylene equivalents, the reading gases that exhibit different responses. In general, any compound with is 10 ppm with a 10.6 eV lamp. The gas being measured is butyl ionization energy (IE) lower than that of the lamp photons can acetate, which has a correction factor of 2.6. Multiplying 10 by 2.6 be measured.* The best way to calibrate a PID to different compounds gives an adjusted butyl acetate value of 26 ppm. Similarly, if the is to use a standard of the gas of interest. However, correction factors gas being measured were trichloroethylene (CF = 0.54), the adjusted have been determined that enable the user to quantify a large number value with a 10 ppm reading would be 5.4 ppm. of chemicals using only a single calibration gas, typically isobutylene. In our PIDs, correction factors can be used in one of three ways: Example 2: With the unit calibrated to read isobutylene equivalents, the reading 1. Calibrate the monitor with isobutylene in the usual fashion to is 100 ppm with a 10.6 eV lamp. The gas measured is m-xylene read in isobutylene equivalents. Manually multiply the reading (CF = 0.43). After downloading this factor, the unit should read about by the correction factor (CF) to obtain the concentration of 43 ppm when exposed to the same gas, and thus read directly in the gas being measured.
    [Show full text]
  • United States Patent Office Patented Aug
    2,849,302 United States Patent Office Patented Aug. 26, 1953 thasaraywarrasants, 2. east one hydrogen atom attached thereto. That is, each of the tertiary halogens is capable of forming hydro 2,849,392 gen halide with a hydrogen atom attached to a different ANTIKNoCK COMPOSITIONS carbon atom which is in a position alpha to the halogen 5 bearing carbon. In this description the term tertiary car Raymond G. Lyben, Detroit, Mich., assigner to Ethy bon atom is defined as a carbon atom which has three Corporation, New York, N. Y., a corporation of Dear other carbon atoms attached thereto by single bonds. Ware Thus, the novel scavenging agents of this invention are No Drawing. Application May 31, 955 certain chlorohydrocarbons, bromohydrocarbons and Seria Rio. 52,284 chlorobromohydrocarbons. The halohydrocarbon scav enging agents of this invention can be derived from al 7 Clains. (C. 44-69) kanes, cycloalkanes, alkenes, cycloalkenes, and hydrocar bon-substituted derivatives thereof. The smallest hydro carbon radical which can provide a scavenger of this in This invention relates to improved antiknock composi s vention contains five carbon atoms; e. g., 1,2-dihalo-1,2- tions. These compositicins encompass antiknock fluids dimethylcyclopropane. In order to provide scavengers and leaded fuels. In particular, this invention relates to having the desirable volatility characteristics with respect a class of hydrocarbons having a particular molecular to the lead antiknock agent, I prefer to employ uniform structure for use as a scavenger with lead antiknock con ly stable scavengers having up to 20 carbon atoms. pounds. Thus, it will be seen that the carbon content of my scav With the discovery of the antiknock effectiveness of or engers ranges from 5 to 20 carbons per molecule.
    [Show full text]
  • Recommended Methods for the Purification of Solvents and Tests for Impurities Nitromethane
    Pure & App!. Chem., Vol. 58, No. 11, pp. 1541—1545, 1986. Printed in Great Britain. © 1986 IUPAC INTERNATIONALUNION OF PURE AND APPLIED CHEMISTRY ANALYTICAL CHEMISTRY DIVISION COMMISSION ON ELECTROANALYTICAL CHEMISTRY* RECOMMENDED METHODS FOR THE PURIFICATION OF SOLVENTS AND TESTS FOR IMPURITIES NITROMETHANE Prepared for publication by J. F. COETZEE and T.-H. CHANG Department of Chemistry, University of Pittsburgh, PA 15260, USA *Membership of the Commission during 1983—85 when the report was prepared was as follows: Chairman: J. Jordan (USA); Secretary: K. Izutsu (Japan); Titular Members: A. K. Covington (UK); J. Juillard (France); R. C. Kapoor (India); E. Pungor (Hungary); Associate Members: W. Davison (UK); R. A. Durst (USA); M. Gross (France); K. M. Kadish (USA); R. Kalvoda (Czechoslovakia); H. Kao (China); Y. Marcus (Israel); T. Mussini (Italy); H. W. NUrnberg (FRG); M. Senda (Japan); N. Tanaka (Japan); K. Tóth (Hungary); National Representatives: D. D. Perrin (Australia); B. Gilbert (Belgium); W. C. Purdy (Canada); A. A. Vlek (Czecho- slovakia); H. Monien (FRG); M. L'Her (France); Gy. Farsang (Hungary); H. C. Gaur (India); W. F. Smyth (Ireland); E. Grushka (Israel); S. R. Cavallari (Italy); W. Frankvoort (Netherlands); Z. Galus (Poland); G. Johansson (Sweden); J. Buffle (Switzerland); H. Thompson (UK); J. G. Osteryoung (USA); I. Piljac (Yugoslavia). Republication of this report is permitted without the need for formal IUPAC permission on condition that an acknowledgement, with full reference together with JUPAC copyright symbol (© 1986 JUPAC), is printed. Publication of a translation into another language is subject to the additional condition of prior approval from the relevant JUPAC NationalAdhering Organization. Recommended methods for the purification of solvents and tests for impurities: nitromethane Themost significant solvent properties of nitromethane are discussed.
    [Show full text]