DOCSLIB.ORG

Direct Analysis in Real Time DART Mass Spectrometry.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Direct Analysis in Real Time DART Mass Spectrometry.Pdf Direct Analysis in Real Time (DARTtm) Mass Spectrometry Robert B. Cody†, James A. Laramée††, J. Michael Nilles†††, and H. Dupont Durst†††† †JEOL USA, Inc. ††EAI Corporation †††Geo-Centers Inc. ††††Edgewood Chemical Biological Center Introduction ion source if too much sample is introduced. sources used in hand-held detectors for chemi- Atmospheric pressure ion sources such as cal weapons agents (CWAs), drugs, and explo- Mass Spectrometry (MS) is one of the atmospheric pressure chemical ionization sives. The discovery that DART could be fastest-growing areas in analytical instrumen- (APCI)[5], electrospray ionization (ESI)[6-8], used for positive-ion and negative-ion non- tation. The use of mass spectrometry in sup- matrix-assisted laser desorption ionization contact detection of materials on surfaces, as port of synthetic, organic, and pharmaceutical (MALDI)[9-10] and atmospheric pressure well as for detection of gases and liquids, led chemistry is well established. Mass spectrome- photoionization (APPI)[11] have broadened to the development of a commercial product. try is also used in materials science, environ- the range of compounds that can be analyzed DART is based on the atmospheric pressure mental research, and forensic chemistry. It has by mass spectrometry. However, these ion interactions of long-lived electronic excited- also evolved into one of the core methods used sources require that samples be exposed to ele- state atoms or vibronic excited-state molecules in biotechnology. However, currently avail- vated temperatures and electrical potentials, with the sample and atmospheric gases. The able ion sources place extreme restrictions on ultraviolet irradiation, laser radiation, or a DART ion source is shown in Figure 1. A gas the speed and convenience of sample analysis high-velocity gas stream. Safety considera- (typically helium or nitrogen) flows through a by mass spectrometry. Here we report a tions require that the ion source be fully chamber where an electrical discharge pro- method for using mass spectrometry to instan- enclosed to protect the operator from harm. duces ions, electrons, and excited-state taneously analyze gases, liquids, and solids in The new ion source reported herein over- (metastable) atoms and molecules. Most of open air at ground potential under ambient comes these limitations. The new technique, the charged particles are removed as the gas conditions. referred to as Direct Analysis in Real Time passes through perforated lenses or grids and Traditional ion sources used in mass spec- (DARTtm), has been coupled to the AccuTOF- only the neutral gas molecules, including trometry require the introduction of samples LCtm atmospheric pressure ionization mass metastable species, remain. A perforated lens into a high vacuum system. Traditional ion spectrometer to permit high-resolution, exact or grid at the exit of the DART provides sever- sources operated in vacuum include electron mass measurements of gases, liquids, and al functions: it prevents ion-ion and ion-elec- ionization (EI)[1], chemical ionization (CI)[2], solids[12,13]. DART successfully sampled tron recombination, it acts as a source of elec- fast atom bombardment (FAB)[3], and field hundreds of chemicals, including chemical trons by surface Penning ionization, and it acts desorption/field ionization (FD/FI)[4]. These agents and their signatures, pharmaceutics, as an electrode to promote ion drift toward the techniques have been used successfully for metabolites, pesticides and environmentally orifice of the mass spectrometer’s atmospheric decades. However, the requirement that sam- significant compounds, peptides and oligosac- pressure interface. ples be introduced into a high vacuum for charides, synthetic organics, organometallics, Several ionization mechanisms are possible, analysis is a severe limitation. Gas or liquid drugs of abuse, explosives, and toxic industrial depending on the polarity and reaction gas, the samples must be introduced through a gas chemicals. These chemicals were detected on a proton affinity and ionization potential of the chromatograph or a specially designed inlet variety of surfaces such as concrete, human analyte, and the presence of additives or system. Solid samples must be introduced by skin, currency, airline boarding passes, fruits dopants. The simplest process is Penning ion- using a direct insertion probe and a vacuum and vegetables, body fluids, cocktail glasses, ization [14] involving transfer of energy from lock system. Direct insertion probes can result and clothing. The composition of drug cap- the excited gas M* to an analyte S having an in vacuum failure and/or contamination of the sules and tablets was directly analyzed. ionization potential lower than the energy of M*. This produces a radical molecular cation S+• and an electron (e-). †11 Dearborn Road, Peabody, Massachusetts, Background and Principle of USA. Operation M* + S Ǟ S+• + M + electron- ††1308 Continental Drive, Suite J, Abingdon, MD 21009 DART grew out of discussions at JEOL Penning ionization is a dominant reaction †††Box 68 Gunpowder Branch, APG, MD USA, Inc. between two of the authors mechanism when nitrogen or neon is used in 21010 (Laramee and Cody) about the possibility of the DART source. Nitrogen or neon ions are ††††Aberdeen Proving Grounds, Maryland developing an atmospheric pressure thermal effectively removed by the electrostatic lenses USA electron source to replace the radioactive and are never observed in the DART back- ( 8) JEOL News Vol.40 No.1 8 (2005) Needle electrode Gas heater Gas electrode Gas in Perforated disk electrodes Gas out Insulator cap Fig. 1 Schematic diagram of the DART ion source. ground mass spectrum. surface Penning ionization as the internal ener- cleavage of the water bond without concomi- When helium is used, the dominant posi- gy of the metastable species increases. tant ion formation. None of these ion sources tive-ion formation mechanism involves the The polarity of the DART ion source is are designed for direct analysis of gases, liq- formation of ionized water clusters followed switched between positive-ion mode and nega- uids, and solids in open air under ambient con- by proton transfer reactions: tive-ion mode by changing the polarity of the ditions. disk electrode and grid. The polarity of the 3 +• 1 - He(2 S) + H2O H2O + He(1 S) + electron discharge needle is not changed, so the plasma Experimental H2O+• + H2O H3O+ + OH• is not interrupted. This permits rapid switch- tm H3O+ + n H2O [(H2O)nH]+ ing between positive and negative modes. A DART source [24] was installed on a tm [(H2O)nH]+ + M MH+ + nH2O Other reactions are possible. The presence JEOL AccuTOF LC time-of-flight mass of traces of dopants such as ammonium (e.g. spectrometer. The DART source replaces the The helium 23S state has an energy of 19.8 from ammonium hydroxide headspace vapor) standard electrospray ionization (ESI) source eV. Its reaction with water is extremely effi- or chloride (e.g. from methylene chloride supplied with the AccuTOF. No vacuum vent cient [15] with the reaction cross section esti- vapor) can modify the chemistry allowing the is required. The ion sources can be exchanged mated at 100 Å2. Because of this extraordinar- chemist to tailor the experiment for specific and made operational within minutes. ily high cross section, DART performance is analyses. The mass spectrometer operates at a con- not affected by humidity. DART produces relatively simple mass stant resolving power of approximately 6000 Negative-ion formation occurs by a differ- spectra characterized by M+; and/or [M+H]+ in (FWHM definition). Typical atmospheric ent mechanism. Electrons (e-) are produced by positive-ion mode, and M-. or [M-H]- in nega- pressure interface conditions are: orifice 1 = Penning ionization or by surface Penning ion- tive-ion mode. Fragment ions are observed for 30V, and both orifice 2 and ring lens are set to ization: some compounds. The degree of fragmenta- 5V. The AccuTOF ion guide voltage is varied tion can be influenced by the choice of gas, the as needed depending on the lowest m/z to be M* + surface Ǟ M + surface + e- temperature, and the AccuTOF orifice 1 poten- measured. Orifice 1 temperature is typically tial. Alkali metal cation attachment and dou- kept warm (80 degrees C) to prevent contami- These electrons are rapidly thermalized by ble-charge ions are not observed. nation. Although there is some electrical collisions with atmospheric pressure gas The mechanism involved in desorption of potential on the exposed orifice 1, the voltage materials from surfaces by DART is less well and current are so low that there is absolutely - Ǟ - e fast + gas e slow characterized. Thermal desorption plays a role no danger to the operator, even with prolonged if the gas stream is heated. However, the direct contact. Thermal electrons undergo electron capture analysis by DART of inorganic materials such The DART source is operated with typical by atmospheric oxygen as sodium perchlorate or organic salts having gas flows between 1.5 and 3 liters per minute. little or no vapor pressure is evidence of other Gas temperature is programmable from ambi- - Ǟ - e slow + O2 O2 processes. It is postulated that the transfer ent temperature up to approximately 350 energy to the surface by metastable atoms and degrees C (gas heater temperature from OFF - to produce O2 , which reacts with the analyte molecules facilitates desorption and ionization. to a maximum of 550 degrees C). Typical to produce anions. The DART negative-ion In contrast with other ion sources that use potentials are: discharge needle 2 kV to 4 kV, reagent mass spectra are virtually identical for metastable species [16-23], the DART ion electrode 1: 100V, grid: 250 V. Gas, liquid, nitrogen, neon, and helium. However, nega- source does not operate under reduced pres- or solid samples positioned in the gap between tive-ion sensitivity increases for DART gases sure, apply a high electrical potential to the the DART source and mass spectrometer ori- in the following order: analyte, or expose the analyte directly to the fice 1 are ionized.
Load more

Recommended publications
  • 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.
    [Show full text]
  • 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.
    [Show full text]
  • Ultra-Performance Liquid Chromatography Coupled to Quadrupole-Orthogonal Time-Of-flight Mass Spectrometry
    RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2004; 18: 2331–2337 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/rcm.1627 Ultra-performance liquid chromatography coupled to quadrupole-orthogonal time-of-flight mass spectrometry Robert Plumb1*, Jose Castro-Perez2, Jennifer Granger1, Iain Beattie3, Karine Joncour3 and Andrew Wright3 1Waters Corporation, Milford, MA, USA 2Waters Corporation, MS Technology Center, Manchester, UK 3AstraZeneca R&D Charnwood, Physical & Metabolic Science, Loughborough, UK Received 19 June 2004; Revised 5 August 2004; Accepted 9 August 2004 Ultra-performance liquid chromatography (UPLC) utilizes sub-2 mm particles with high linear sol- vent velocities to effect dramatic increases in resolution, sensitivity and speed of analysis. The reduction in particle size to below 2 mm requires instrumentation that can operate at pressures in the 6000–15 000 psi range. The typical peak widths generated by the UPLC system are in the order of 1–2 s for a 10-min separation. In the present work this technology has been applied to the study of in vivo drug metabolism, in particular the analysis of drug metabolites in bile. The reduction in peak width significantly increases analytical sensitivity by three- to five-fold, and the reduction in peak width, and concomitant increase in peak capacity, significantly reduces spectral overlap resulting in superior spectral quality in both MS and MS/MS modes. The application of UPLC/ MS resulted in the detection of additional drug metabolites, superior separation and improved spectral quality. Copyright # 2004 John Wiley & Sons, Ltd. The detection and identification of drug metabolites is crucial Liquid chromatography/mass spectrometry (LC/MS) and to both the drug discovery and development processes, LC/MS/MS have become the mainstay of the drug metabo- although in these two areas the emphasis is slightly different.
    [Show full text]
  • 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.
    [Show full text]
  • 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
    [Show full text]
  • Modern Mass Spectrometry
    Modern Mass Spectrometry MacMillan Group Meeting 2005 Sandra Lee Key References: E. Uggerud, S. Petrie, D. K. Bohme, F. Turecek, D. Schröder, H. Schwarz, D. Plattner, T. Wyttenbach, M. T. Bowers, P. B. Armentrout, S. A. Truger, T. Junker, G. Suizdak, Mark Brönstrup. Topics in Current Chemistry: Modern Mass Spectroscopy, pp. 1-302, 225. Springer-Verlag, Berlin, 2003. Current Topics in Organic Chemistry 2003, 15, 1503-1624 1 The Basics of Mass Spectroscopy ! Purpose Mass spectrometers use the difference in mass-to-charge ratio (m/z) of ionized atoms or molecules to separate them. Therefore, mass spectroscopy allows quantitation of atoms or molecules and provides structural information by the identification of distinctive fragmentation patterns. The general operation of a mass spectrometer is: "1. " create gas-phase ions "2. " separate the ions in space or time based on their mass-to-charge ratio "3. " measure the quantity of ions of each mass-to-charge ratio Ionization sources ! Instrumentation Chemical Ionisation (CI) Atmospheric Pressure CI!(APCI) Electron Impact!(EI) Electrospray Ionization!(ESI) SORTING DETECTION IONIZATION OF IONS OF IONS Fast Atom Bombardment (FAB) Field Desorption/Field Ionisation (FD/FI) Matrix Assisted Laser Desorption gaseous mass ion Ionisation!(MALDI) ion source analyzer transducer Thermospray Ionisation (TI) Analyzers quadrupoles vacuum signal Time-of-Flight (TOF) pump processor magnetic sectors 10-5– 10-8 torr Fourier transform and quadrupole ion traps inlet Detectors mass electron multiplier spectrum Faraday cup Ionization Sources: Classical Methods ! Electron Impact Ionization A beam of electrons passes through a gas-phase sample and collides with neutral analyte molcules (M) to produce a positively charged ion or a fragment ion.
    [Show full text]
  • Fundamentals of Biological Mass Spectrometry and Proteomics
    Fundamentals of Biological Mass Spectrometry and Proteomics Steve Carr Broad Institute of MIT and Harvard Modern Mass Spectrometer (MS) Systems Orbitrap Q-Exactive Triple Quadrupole Discovery/Global Experiments Targeted MS MS systems used for proteomics have 4 tasks: • Create ions from analyte molecules • Separate the ions based on charge and mass • Detect ions and determine their mass-to-charge • Select and fragment ions of interest to provide structural information (MS/MS) Electrospray MS: ease of coupling to liquid-based separation methods has made it the key technology in proteomics Possible Sample Inlets Syringe Pump Sample Injection Loop Liquid Autosampler, HPLC Capillary Electrophoresis Expansion of the Ion Formation and Sampling Regions Nitrogen Drying Gas Electrospray Atmosphere Vacuum Needle 3- 5 kV Liquid Nebulizing Gas Droplets Ions Containing Solvated Ions Isotopes Most elements have more than one stable isotope. For example, most carbon atoms have a mass of 12 Da, but in nature, 1.1% of C atoms have an extra neutron, making their mass 13 Da. Why do we care? Mass spectrometers “see” the isotope peaks provided the resolution is high enough. If an MS instrument has resolution high enough to resolve these isotopes, better mass accuracy is achieved. Stable isotopes of most abundant elements of peptides Element Mass Abundance H 1.0078 99.985% 2.0141 0.015 C 12.0000 98.89 13.0034 1.11 N 14.0031 99.64 15.0001 0.36 O 15.9949 99.76 16.9991 0.04 17.9992 0.20 Monoisotopic mass and isotopes We use instruments that resolve the isotopes enabling us to accurately measure the monoisotopic mass MonoisotopicMonoisotopic mass; all 12C, mass no 13C atoms corresponds to 13 lowestOne massC atom peak Two 13C atoms Angiotensin I (MW = 1295.6) (M+H)+ = C62 H90 N17 O14 TheWhen monoisotopic the isotopes mass of aare molecule clearly is the resolved sum of the the accurate monoisotopic masses for the massmost abundant isotope of each element present.
    [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]
  • Cryogenic Micro-Calorimeters for Mass Spectrometry of Kev Neutral Atoms
    Journal of Physics: Conference Series PAPER • OPEN ACCESS Related content - The status of the micro-calorimeter at the Cryogenic micro-calorimeters for mass Shanghai EBIT - The Variability of the Recombination of spectrometry of keV neutral atoms and molecules Hydrogen Atoms on Metal Surfaces - SQUID gradiometer for ultra-low To cite this article: O Novotný et al 2015 J. Phys.: Conf. Ser. 635 032023 temperature magnetic micro-calorimeter View the article online for updates and enhancements. This content was downloaded from IP address 129.13.72.197 on 04/11/2020 at 09:19 XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC2015) IOP Publishing Journal of Physics: Conference Series 635 (2015) 032023 doi:10.1088/1742-6596/635/3/032023 Cryogenic micro-calorimeters for mass spectrometry of keV neutral atoms and molecules O Novotn´y∗;y 1, S Allgeierz, C Enssz, A Fleischmannz, L Gamerz, D Hengstlerz, S Kempfz, C Krantz∗, A Pabingerz, C Piesz, D W Saviny, D Schwalm∗;⋄, A Wolf∗ 2 ∗ Max Planck Institute for Nuclear Physics, D-69117 Heidelberg, Germany y Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA z Kirchhoff Institute for Physics, Heidelberg University, D-69120 Heidelberg, Germany ⋄ Faculty of Physics, Weizmann Institute of Science, Rehovot 76100, Israel Synopsis We demonstrate the capability of micro-calorimeters to detect and mass-resolve neutral atoms and molecules at ∼ keV energies, reaching single H-atom resolution. Mass spectrometric identification of fragmen- also studied in detail the MMC response function tation products is one of the most important for molecular projectiles of masses up to 56 amu.
    [Show full text]
  • An Organic Chemist's Guide to Electrospray Mass Spectrometric
    molecules Review An Organic Chemist’s Guide to Electrospray Mass Spectrometric Structure Elucidation Arnold Steckel 1 and Gitta Schlosser 2,* 1 Hevesy György PhD School of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary; [email protected] 2 Department of Analytical Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, 1117 Budapest, Hungary * Correspondence: [email protected] Received: 16 January 2019; Accepted: 8 February 2019; Published: 10 February 2019 Abstract: Tandem mass spectrometry is an important tool for structure elucidation of natural and synthetic organic products. Fragmentation of odd electron ions (OE+) generated by electron ionization (EI) was extensively studied in the last few decades, however there are only a few systematic reviews available concerning the fragmentation of even-electron ions (EE+/EE−) produced by the currently most common ionization techniques, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). This review summarizes the most important features of tandem mass spectra generated by collision-induced dissociation fragmentation and presents didactic examples for the unexperienced users. Keywords: tandem mass spectrometry; MS/MS fragmentation; collision-induced dissociation; CID; ESI; structure elucidation 1. Introduction Electron ionization (EI), a hard ionization technique, is the method of choice for analyses of small (<1000 Da), nonpolar, volatile compounds. As its name implies, the technique involves ionization by electrons with ~70 eV energy. This energy is high enough to yield very reproducible mass spectra with a large number of fragments. However, these spectra frequently lack the radical type molecular ions (M+) due to the high internal energy transferred to the precursors [1].
    [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]
  • 1 Introduction of Mass Spectrometry and Ambient Ionization Techniques
    1 1 Introduction of Mass Spectrometry and Ambient Ionization Techniques Yiyang Dong, Jiahui Liu, and Tianyang Guo College of Life Science & Technology, Beijing University of Chemical Technology, No. 15 Beisanhuan East Road, Chaoyang District, Beijing, 100029, China 1.1 Evolution of Analytical Chemistry and Its Challenges in the Twenty-First Century The Chemical Revolution began in the eighteenth century, with the work of French chemist Antoine Lavoisier (1743–1794) representing a fundamental watershed that separated the “modern chemistry” era from the “protochemistry” era (Figure 1.1). However, analytical chemistry, a subdiscipline of chemistry, is an ancient science and its metrological tools, basic applications, and analytical processes can be dated back to early recorded history [1]. In chronological spans covering ancient times, the middle ages, the era of the nineteenth century, and the three chemical revolutionary periods, analytical chemistry has successfully evolved from the verge of the nineteenth century to modern and contemporary times, characterized by its versatile traits and unprecedented challenges in the twenty-first century. Historically, analytical chemistry can be termed as the mother of chemistry, as the nature and the composition of materials are always needed to be iden- tified first for specific utilizations subsequently; therefore, the development of analytical chemistry has always been ahead of general chemistry [2]. During pre-Hellenistic times when chemistry did not exist as a science, various ana- lytical processes, for example, qualitative touchstone method and quantitative fire-assay or cupellation scheme have been in existence as routine quality control measures for the purpose of noble goods authentication and anti-counterfeiting practices. Because of the unavailability of archeological clues for origin tracing, the chemical balance and the weights, as stated in the earliest documents ever found, was supposed to have been used only by the Gods [3].
    [Show full text]