DOCSLIB.ORG

Proton Transfer Reaction Mass Spectrometry (Ptr-Ms)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

28 PROTON TRANSFER REACTION MASS SPECTROMETRY ( PTR - MS ) Yujie Wang , Chengyin Shen , Jianquan Li , Haihe Jiang , and Yannan Chu 28.1 INTRODUCTION is measured. If a chromatographic separation method is not used prior to MS, then the resulting mass spectra Proton transfer reaction mass spectrometry ( PTR - MS ) from EI may be so complicated that identifi cation and was fi rst developed at the Institute of Ion Physics of quantifi cation of the compounds can be very diffi cult. In Innsbruck University in the 1990s. Nowadays, PTR - MS PTR - MS instrument, the hollow cathode discharge is is a well - developed and commercially available tech- served as a typical ion source [1] , although plane elec- nique for the on - line monitoring of trace volatile organic trode direct current discharge [2] and radioactive ion- compound s ( VOC s) down to parts per trillion by volume ization sources [3] recently have been reported. All of (ppt) level. PTR - MS has some advantages such as rapid the ion sources are used to generate clean and intense + response, soft chemical ionization ( CI ), absolute quan- primary reagent ions like H3 O . Water vapor is a regular tifi cation, and high sensitivity. In general, a standard gas in the hollow cathode discharge where H2 O mole- PTR - MS instrument consists of external ion source, cule can be ionized according to the following ways [4] : drift tube, and mass analysis detection system. Figure 28.1 illustrates the basic composition of the PTR - MS + ee+→++HO22 H O 2, (28.1) instrument constructed in our laboratory using a quad- +→+++ rupole mass spectrometer as the detection system. eeHO2 H OH 2, (28.2) + ee+→++HO22 O H 2, (28.3) 28.1.1 Ion Source + ee+→HO22 HO +2. (28.4) Perhaps the most remarkable feature of PTR - MS is the special CI mode through well - controlled proton trans- The above ions are injected into a short source drift fer reaction, in which the neutral molecule M may be region and further react with H2 O ultimately leading to + converted to a nearly unique protonated molecular ion the formation of H3 O via ion – molecule reactions: MH+ . This ionization mode is completely different from ++ traditional mass spectrometry (MS) where electron HHOHOH22+→ 2 + 2 (28.5a) + impact ( EI ) with energy of 70 eV is often used to ionize →+HO3 H (28.5b) chemicals like VOCs. Although the EI source has been ++ HHOHOH+→ + (28.6) widely used with the commercial MS instruments most 22 ++ coupled with a variety of chromatography techniques, OHOHOO+→22 + (28.7) these MS platforms have a major defi ciency: in the ++ OH+→ H23 O H O + O (28.8a) course of ionization, the molecule will be dissociated to + →+HO OH (28.8b) many fragment ions. This extensive fragmentation may 2 ++ result in complex mass spectra especially when a mixture HO223+→ HO HO + OH (28.9) Mass Spectrometry Handbook, First Edition. Edited by Mike S. Lee. © 2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc. 605 606 PROTON TRANSFER REACTION MASS SPECTROMETRY (PTR-MS) HC SD quadrupole mass filter SEM Water in Water out Water IC sample inlet turbo pump turbo pump ion drift tube ion detection system source FIGURE 28.1 Schematic diagram of the PTR - MS instrument that contains a hollow cathode (HC), a source drift (SD) region, an intermediate chamber (IC), and a secondary electron multiplier (SEM). Unfortunately, the water vapor in the source drift 28.1.2 Drift Tube region inevitably can form a few of cluster ions + The drift tube consists of a number of metal rings that H O (H O) via the three - body combination process 3 2 n are equally separated from each other by insulated rings. Between the adjacent metal rings, a series of resis- + + HO3212() HOnn− ++→ HO A HO 32 () HO +≥ A (),n 1 tors is connected. A high voltage power supplier pro- duces a voltage gradient and establishes a homogeneous (28.10) electric fi eld along the axis of the ion reaction drift tube. The primary H O + ions are extracted into the ion where A is a third body. In addition, small amounts of 3 + + reaction region and can react with analyte M present in NO and O2 ions occurred due to sample air diffusion the sample air, which through the inlet is added to the into the source region from the downstream drift tube. upstream of the ion reaction drift tube. According to Thus, an inlet of venturi type has been employed on the values of proton affi nity ( PA ) (see Table 28.1 ), the some PTR - MS systems to prevent air from entering the + + reagent ion H3 O does not react with the main compo- source drift region [5,6] . At last, the H3 O ions produced > nents in air like N2 , O2 , and CO2 . In contrast, the reagent in the ion source can have the purity up to 99.5%. Thus, ion can undergo proton transfer reaction with M as long unlike the selected ion fl ow tube mass spectrometry as the PA of M exceeds that of H O [6] : (SIFT - MS) technique [7] , the mass fi lter for the primary 2 + ionic selection is not needed and the H 3 O ions can be MHO+→+++ MHHO. (28.11) directly injected into the drift tube. In some PTR - MS, 32 + 6∼ 7 the ion intensity of H3 O is available at 10 10 counts Thus, the ambient air can be directly introduced to per second on a mass spectrometer installed in the achieve an on - line measurement in the PTR - MS opera- vacuum chamber at the end of the drift tube. Eventually, tion. Due to the presence of electric fi eld, in the reaction the limitation of detection of PTR - MS can reach low region, the ion energy is closely related to the reduced - ppt level. fi eld E/N , where E is the electric fi eld and N is the + Instead of H3 O , other primary reagent ions, such as number density of gas in the drift tube. In a typical + + + NH4 , NO , and O2 , have been investigated in PTR - MS PTR - MS measurement, E/N is required to set to an instrument [8 – 10] . Because the ion chemistry for these appropriate value normally in the range of 120 ∼ 160 Td ions is not only proton transfer reaction, the technique (1 Td = 1 0 − 17 Vcm 2 /molecule), which may restrain the + is sometimes called CI reaction MS. However, the formation of the water cluster ions H3 O (H2 O)n potential benefi ts of using these alternative reagents are (n = 1 – 3) to avoid the ligand switch reaction with + usually minimal, and to our knowledge, H3 O is still the analyte M [6] : dominant reagent ion employed in PTR - MS research +++→ + [1,6,11,12] . HO32() HOnn M HO 3212 () HO− M HO . (28.12) INTRODUCTION 607 TABLE 28.1 Proton Affi nities of Some Compounds mass spectrometer ( TOF - MS ) [14 – 16] , ion trap mass Compound Molecular Molecular Proton spectrometer (IT - MS) [17] , and linear ion trap mass Formula Weight Affi nity [13] spectrometer (LIT - MS) [18] . These MS techniques have (kJ/mol) been used to distinguish isomeric/isobaric compounds as discussed in the later section. Helium He 4 177.8 Neon Ne 20 198.8 Argon Ar 40 369.2 28.1.4 Absolute Quantifi cation Oxygen O2 32 421 Normally, PTR - MS can determine the absolute concen- Nitrogen N2 28 493.8 Carbon dioxide CO2 44 540.5 trations of trace VOCs according to well - established Methane CH4 16 543.5 ion – molecular reaction kinetics. If trace analyte M + + Carbon monoxide CO 28 594 reacts with H3 O , then the H3 O signal does not decline Ethane C2 H6 30 596.3 signifi cantly and can be deemed to be a constant. Thus, + Ethylene C2 H4 28 680.5 the density of product ions [MH ] at the end of the drift Water H2O 18 691 tube is given in Equation 28.13 [6] : Hydrogen sulfi de H2 S 34 705 Hydrogen cyanide HCN 27 712.9 ++−=−kt[]M Formic acid HCOOH 46 742 [][](),MH H30 O 1 e (28.13) Benzene C6 H6 78 750.4 + Propene C3 H6 42 751.6 where [H3 O ]0 is the density of reagent ions at the end Methanol CH3 OH 32 754.3 of the drift tube in the absence of analyte M, k is the Acetaldehyde CH3 COH 44 768.5 rate constant of reaction 28.11, and t is the average reac- Ethanol C2 H5 OH 46 776.4 tion time the ions spend in the drift tube. In the trace Acetonitrile CH3 CN 41 779.2 analysis case k [M] t << 1, Equation 28.13 can be further Acetic acid CH3 COOH 60 783.7 deduced to the following form Toluene C7 H8 92 784 Propanal CH3 CH2 COH 58 786 + O - xylene C H 106 796 []MH 1 8 10 []M = . Acetone CH COCH 58 812 + (28.14) 3 3 []HO30kt Isoprene CH2 C(CH3 ) 68 826.4 CHCH2 Ammonia NH3 17 853.6 Equation 28.14 is often used in a conventional Aniline C6 H7 N 93 882.5 PTR - MS measurement. However, when the concentra- tion of analyte M is rather high, the intensity change of + reagent ions H3 O is not neglectable. In this case, the relation k [M] t << 1 is not tenable; therefore, the regular Equation 28.14 is no longer suitable for concentration However, a higher reduced - fi eld E/N can cause the determination. For a more reliable measurement, the collision - induced dissociation (CID) of the protonated following Equation 28.15 , deduced from Equation 28.13 , products, thereby complicating the identifi cation of can be used to determine the concentration of analyte detected analytes.
Recommended publications
  • Molecular Regulation of Plant Monoterpene Biosynthesis in Relation to Fragrance

    Molecular Regulation of Plant Monoterpene Biosynthesis in Relation to Fragrance

    Molecular Regulation of Plant Monoterpene Biosynthesis In Relation To Fragrance Mazen K. El Tamer Promotor: Prof. Dr. A.G.J Voragen, hoogleraar in de Levensmiddelenchemie, Wageningen Universiteit Co-promotoren: Dr. ir. H.J Bouwmeester, senior onderzoeker, Business Unit Celcybernetica, Plant Research International Dr. ir. J.P Roozen, departement Agrotechnologie en Voedingswetenschappen, Wageningen Universiteit Promotiecommissie: Dr. M.C.R Franssen, Wageningen Universiteit Prof. Dr. J.H.A Kroeze, Wageningen Universiteit Prof. Dr. A.J van Tunen, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam. Prof. Dr. R.G.F Visser, Wageningen Universiteit Mazen K. El Tamer Molecular Regulation Of Plant Monoterpene Biosynthesis In Relation To Fragrance Proefschrift ter verkrijging van de graad van doctor op gezag van de rector magnificus van Wageningen Universiteit, Prof. dr. ir. L. Speelman, in het openbaar te verdedigen op woensdag 27 november 2002 des namiddags te vier uur in de Aula Mazen K. El Tamer Molecular Regulation Of Plant Monoterpene Biosynthesis In Relation To Fragrance Proefschrift Wageningen Universiteit ISBN 90-5808-752-2 Cover and Invitation Design: Zeina K. El Tamer This thesis is dedicated to my Family & Friends Contents Abbreviations Chapter 1 General introduction and scope of the thesis 1 Chapter 2 Monoterpene biosynthesis in lemon (Citrus limon) cDNA isolation 21 and functional analysis of four monoterpene synthases Chapter 3 Domain swapping of Citrus limon monoterpene synthases: Impact 57 on enzymatic activity and
  • On the History of the Radiation Reaction1 Kirk T

    On the History of the Radiation Reaction1 Kirk T

    On the History of the Radiation Reaction1 Kirk T. McDonald Joseph Henry Laboratories, Princeton University, Princeton, NJ 08544 (May 6, 2017; updated March 18, 2020) 1 Introduction Apparently, Kepler considered the pointing of comets’ tails away from the Sun as evidence for radiation pressure of light [2].2 Following Newton’s third law (see p. 83 of [3]), one might suppose there to be a reaction of the comet back on the incident light. However, this theme lay largely dormant until Poincar´e (1891) [37, 41] and Planck (1896) [46] discussed the effect of “radiation damping” on an oscillating electric charge that emits electromagnetic radiation. Already in 1892, Lorentz [38] had considered the self force on an extended, accelerated charge e, finding that for low velocity v this force has the approximate form (in Gaussian units, where c is the speed of light in vacuum), independent of the radius of the charge, 3e2 d2v 2e2v¨ F = = . (v c). (1) self 3c3 dt2 3c3 Lorentz made no connection at the time between this force and radiation, which connection rather was first made by Planck [46], who considered that there should be a damping force on an accelerated charge in reaction to its radiation, and by a clever transformation arrived at a “radiation-damping” force identical to eq. (1). Today, Lorentz is often credited with identifying eq. (1) as the “radiation-reaction force”, and the contribution of Planck is seldom acknowledged. This note attempts to review the history of thoughts on the “radiation reaction”, which seems to be in conflict with the brief discussions in many papers and “textbooks”.3 2 What is “Radiation”? The “radiation reaction” would seem to be a reaction to “radiation”, but the concept of “radiation” is remarkably poorly defined in the literature.
  • Classical Mechanics

    Classical Mechanics

    Classical Mechanics Hyoungsoon Choi Spring, 2014 Contents 1 Introduction4 1.1 Kinematics and Kinetics . .5 1.2 Kinematics: Watching Wallace and Gromit ............6 1.3 Inertia and Inertial Frame . .8 2 Newton's Laws of Motion 10 2.1 The First Law: The Law of Inertia . 10 2.2 The Second Law: The Equation of Motion . 11 2.3 The Third Law: The Law of Action and Reaction . 12 3 Laws of Conservation 14 3.1 Conservation of Momentum . 14 3.2 Conservation of Angular Momentum . 15 3.3 Conservation of Energy . 17 3.3.1 Kinetic energy . 17 3.3.2 Potential energy . 18 3.3.3 Mechanical energy conservation . 19 4 Solving Equation of Motions 20 4.1 Force-Free Motion . 21 4.2 Constant Force Motion . 22 4.2.1 Constant force motion in one dimension . 22 4.2.2 Constant force motion in two dimensions . 23 4.3 Varying Force Motion . 25 4.3.1 Drag force . 25 4.3.2 Harmonic oscillator . 29 5 Lagrangian Mechanics 30 5.1 Configuration Space . 30 5.2 Lagrangian Equations of Motion . 32 5.3 Generalized Coordinates . 34 5.4 Lagrangian Mechanics . 36 5.5 D'Alembert's Principle . 37 5.6 Conjugate Variables . 39 1 CONTENTS 2 6 Hamiltonian Mechanics 40 6.1 Legendre Transformation: From Lagrangian to Hamiltonian . 40 6.2 Hamilton's Equations . 41 6.3 Configuration Space and Phase Space . 43 6.4 Hamiltonian and Energy . 45 7 Central Force Motion 47 7.1 Conservation Laws in Central Force Field . 47 7.2 The Path Equation .
  • Power Sources Challenge

    Power Sources Challenge

    POWER SOURCES CHALLENGE FUSION PHYSICS! A CLEAN ENERGY Summary: What if we could harness the power of the Sun for energy here on Fusion reactions occur when two nuclei come together to form one Earth? What would it take to accomplish this feat? Is it possible? atom. The reaction that happens in the sun fuses two Hydrogen atoms together to produce Helium. It looks like this in a very simplified way: Many researchers including our Department of Energy scientists and H + H He + ENERGY. This energy can be calculated by the famous engineers are taking on this challenge! In fact, there is one DOE Laboratory Einstein equation, E = mc2. devoted to fusion physics and is committed to being at the forefront of the science of magnetic fusion energy. Each of the colliding hydrogen atoms is a different isotope of In order to understand a little more about fusion energy, you will learn about hydrogen, one deuterium and one the atom and how reactions at the atomic level produce energy. tritium. The difference in these isotopes is simply one neutron. Background: It all starts with plasma! If you need to learn more about plasma Deuterium has one proton and one physics, visit the Power Sources Challenge plasma activities. neutron, tritium has one proton and two neutrons. Look at the The Fusion Reaction that happens in the SUN looks like this: illustration—do you see how the mass of the products is less than the mass of the reactants? That is called a mass deficit and that difference in mass is converted into energy.
  • Physics 101 Today Chapter 5: Newton's Third

    Physics 101 Today Chapter 5: Newton's Third

    Physics 101 Today Chapter 5: Newton’s Third Law First, let’s clarify notion of a force : Previously defined force as a push or pull. Better to think of force as an interaction between two objects. You can’t push anything without it pushing back on you ! Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Newton’s 3 rd Law - often called “action-reaction ” Eg. Leaning against a wall. You push against the wall. The wall is also pushing on you, equally hard – normal/support force. Now place a piece of paper between the wall and hand. Push on it – it doesn’t accelerate must be zero net force. The wall is pushing equally as hard (normal force) on the paper in the opposite direction to your hand, resulting in zero Fnet . This is more evident when hold a balloon against the wall – it is squashed on both sides. Eg. You pull on a cart. It accelerates. The cart pulls back on you (you feel the rope get tighter). Can call your pull the “ action ” and cart’s pull the “ reaction ”. Or, the other way around. • Newton’s 3 rd law means that forces always come in action -reaction pairs . It doesn’t matter which is called the action and which is called the reaction. • Note: Action-reaction pairs never act on the same object Examples of action-reaction force pairs In fact it is the road’s push that makes the car go forward. Same when we walk – push back on floor, floor pushes us forward.
  • HW 6, Question 1: Forces in a Rotating Frame

    HW 6, Question 1: Forces in a Rotating Frame

    HW 6, Question 1: Forces in a Rotating Frame Consider a solid platform, like a \merry-go round", that rotates with respect to an inertial frame of reference. It is oriented in the xy plane such that the axis of rotation is in the z-direction, i.e. ! = !z^, which we can take to point out of the page. Now, let us also consider a person walking on the rotating platform, such that this person is walking radially outward on the platform with respect to their (non-inertial) reference frame with velocity v = vr^. In what follows for Question 1, directions in the non-inertial reference frame (i.e. the frame of the walking person) are defined in the following manner: the x0-direction points directly outward from the center of the merry-go round; the y0 points in the tangential direction of rotation in the plane of the platform; and the z0-direction points out of the page, and in the same direction as the z-direction for the inertial reference frame. (a) Identify all forces. Since the person's reference frame is non-inertial, we need to account for the various fictitious forces given the description above, as well as any other external/reaction forces. The angular rate of rotation is constant, and so the Euler force Feul = m(!_ × r) = ~0. The significant forces acting on the person are: 0 • the force due to gravity, Fg = mg = mg(−z^ ), 2 0 • the (fictitious) centrifugal force, Fcen = m! × (! × r) = m! rx^ , 0 • the (fictitious) Coriolis force, Fcor = 2mv × ! = 2m!v(−y^ ), • the normal force the person experiences from the rotating platform N = Nz^0, and • a friction force acting on the person, f, in the x0y0 plane.
  • And Their OH Reactivity in Various Agro-Ecosystems Sandy Bsaibes

    And Their OH Reactivity in Various Agro-Ecosystems Sandy Bsaibes

    Characterization of biogenic volatile organic compounds (BVOCs) and their OH reactivity in various agro-ecosystems Sandy Bsaibes To cite this version: Sandy Bsaibes. Characterization of biogenic volatile organic compounds (BVOCs) and their OH reactivity in various agro-ecosystems. Global Changes. Université Paris-Saclay, 2019. English. NNT : 2019SACLV093. tel-02614381 HAL Id: tel-02614381 https://tel.archives-ouvertes.fr/tel-02614381 Submitted on 20 May 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Characterization of biogenic volatile organic compounds and their OH reactivity in various : 2019SACLV093 agro-ecosystems NNT Thèse de doctorat de l’Université Paris-Saclay Préparée à l’Université de Versailles Saint-Quentin-en-Yvelines Ecole doctorale n°129 Sciences de l’Environnement d’île-de-France (SEIF) Spécialité de doctorat : chimie atmosphérique Thèse présentée et soutenue à Gif-sur-Yvette, le 12 Décembre 2019 par Sandy Bsaibes Composition du Jury : Didier Hauglustaine Directeur de Recherche, LSCE, CNRS Président Agnès Borbon Chargée de Recherche, LaMP, CNRS Rapporteur Jonathan Williams Senior Scientist, MPIC Rapporteur Corinne Jambert Maître de conférences, LA Examinateur Benjamin Loubet Directeur de Recherche, Ecosys, INRA Examinateur Valérie Gros Directeur de Recherche, LSCE, CNRS Directeur de thèse Contents Acknowledgements ..............................................................................................................................
  • Hinokitiol Production in Suspension Cells of Thujopsis Dolabrata Var

    Hinokitiol Production in Suspension Cells of Thujopsis Dolabrata Var

    55 Original Papers Plant Tissue Culture Letters, 12(1), 55-61(1995) Hinokitiol Production in Suspension Cells of Thujopsis dolabrata var. hondai Makino Ryo FUJII, Kazuo OZAKI, Migifumi INO and Hitoshi WATANABE Integrated Technology Laboratories, Takeda Chemical Industries, Ltd. 11, Ichijoji-takenouchi-cho, Sakyo-ku, Kyoto 606 Japan (Received May 19, 1994) (Accepted October 8, 1994) Suspension cells of Thujopsis dolabrata var. hondai Makino were used as the material for studying the culture conditions by a two-step culture method (cell growth step and secondary metabolite production step) for the production of hinokitiol (Q-thujaplicin). Murashige and Skoog's (MS) medium containing N03-N and NH4-N in the ratio 3-5:1 (total nitrogen 30-75 mM) with 1.0mg/l NAA and 0.2mg/l TDZ was most desirable for cell growth (MS-O medium). The growth showed 14-fold increase after 30 days of culture in this medium. A higher ratio of NH4-N to total nitrogen resulted in hinokitiol accumulation in the cells. When the cells were transferred to the modified MS-O medium with the ratio of N03-N:NH4-N changed to 1:2 (MS-PC medium), an increase of hinokitiol level was observed. Also feeding acetates to the medium enhanced hinokitiol accumula- tion considerably. The highest hinokitiol content of 422tg/g FW was obtained when the cells were cultured in MS-O medium supplemented with 4.3mM acetic acid. Introduction An irregular monoterpene hinokitiol (B-thujaplicin) is widely present in the heartwood of the families Cupressaceae1). Hinokitiol has antimicrobial properties, and recently it has been indicated that hinokitiol suppresses ethylene synthesis and respiration of some fruits and vegetables.
  • A Short History of Physics (Pdf)

    A Short History of Physics (Pdf)

    A Short History of Physics Bernd A. Berg Florida State University PHY 1090 FSU August 28, 2012. References: Most of the following is copied from Wikepedia. Bernd Berg () History Physics FSU August 28, 2012. 1 / 25 Introduction Philosophy and Religion aim at Fundamental Truths. It is my believe that the secured part of this is in Physics. This happend by Trial and Error over more than 2,500 years and became systematic Theory and Observation only in the last 500 years. This talk collects important events of this time period and attaches them to the names of some people. I can only give an inadequate presentation of the complex process of scientific progress. The hope is that the flavor get over. Bernd Berg () History Physics FSU August 28, 2012. 2 / 25 Physics From Acient Greek: \Nature". Broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves. The universe is commonly defined as the totality of everything that exists or is known to exist. In many ways, physics stems from acient greek philosophy and was known as \natural philosophy" until the late 18th century. Bernd Berg () History Physics FSU August 28, 2012. 3 / 25 Ancient Physics: Remarkable people and ideas. Pythagoras (ca. 570{490 BC): a2 + b2 = c2 for rectangular triangle: Leucippus (early 5th century BC) opposed the idea of direct devine intervention in the universe. He and his student Democritus were the first to develop a theory of atomism. Plato (424/424{348/347) is said that to have disliked Democritus so much, that he wished his books burned.
  • Comparison of Biogenic Volatile Organic Compound Emissions from Broad Leaved and Coniferous Trees in Turkey

    Comparison of Biogenic Volatile Organic Compound Emissions from Broad Leaved and Coniferous Trees in Turkey

    Environmental Impact II 647 Comparison of biogenic volatile organic compound emissions from broad leaved and coniferous trees in Turkey Y. M. Aydin1, B. Yaman1, H. Koca1, H. Altiok1, Y. Dumanoglu1, M. Kara1, A. Bayram1, D. Tolunay2, M. Odabasi1 & T. Elbir1 1Department of Environmental Engineering, Faculty of Engineering, Dokuz Eylul University, Turkey 2Department of Soil Science and Ecology, Faculty of Forestry, Istanbul University, Turkey Abstract Biogenic volatile organic compound (BVOC) emissions from thirty-eight tree species (twenty broad leaved and eighteen coniferous) grown in Turkey were measured. BVOC samples were collected with a specialized dynamic enclosure technique in forest areas where these tree species are naturally grown. In this method, the branches were enclosed in transparent nalofan bags maintaining their natural conditions and avoiding any source of stress. The air samples from the inlet and outlet of the bags were collected on an adsorbent tube containing Tenax. Samples were analyzed using a thermal desorption (TD) and gas chromatography mass spectrometry (GC/MS) system. Sixty-five BVOC compounds were analyzed in five major groups: isoprene, monoterpenes, sesquiterpens, oxygenated sesquiterpenes and other oxygenated VOCs. Emission factors were calculated and adjusted to standard conditions (1000 μmol/m2 s photosynthetically active radiation-PAR and 30°C temperature). Consistent with the literature, broad leaved trees emitted mainly isoprene while the coniferous trees emitted mainly monoterpenes. Even though fir species are coniferous trees, they emitted significant amounts of isoprene in addition to monoterpenes. Oak species showed a large inter-species variability in their emissions. Pine species emitted mainly monoterpenes and substantial amounts of oxygenated compounds. Keywords: BVOC emissions, dynamic enclosure system, emission factor, Turkey.
  • Development and Applications of Proton Transfer Reaction-Mass Spectrometry for Homeland Security: Trace Detection of Explosives

    Development and Applications of Proton Transfer Reaction-Mass Spectrometry for Homeland Security: Trace Detection of Explosives

    DEVELOPMENT AND APPLICATIONS OF PROTON TRANSFER REACTION-MASS SPECTROMETRY FOR HOMELAND SECURITY: TRACE DETECTION OF EXPLOSIVES by Ramón González-Méndez, MSc A thesis submitted to the University of Birmingham for the degree of DOCTOR OF PHILOSOPHY School of Physics and Astronomy The University of Birmingham, UK February 2017 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. Abstract This thesis investigates the challenging task of sensitive and selective trace detection of explosive compounds by means of proton transfer reaction mass spectrometry (PTR-MS). In order to address this, new analytical strategies and hardware improvements, leading to new methodologies and analytical tools, have been developed and tested. These are, in order of the Chapters presented in this thesis, the switching of reagent ions, the implementation of a novel thermal desorption unit, and the use of an ion funnel drift tube or fast reduced electric field switching to modify the ion chemistry. In addition to these, a more fundamental study has been undertaken to investigate the reactions of picric acid (PiA) with a number of different reagent ions. The novel approaches described in this thesis have improved the PTR-MS technique by making it more versatile in terms of its analytical performance, namely providing assignment of chemical compounds with high confidence.
  • Determination of Terpenoid Content in Pine by Organic Solvent Extraction and Fast-Gc Analysis

    Determination of Terpenoid Content in Pine by Organic Solvent Extraction and Fast-Gc Analysis

    ORIGINAL RESEARCH published: 25 January 2016 doi: 10.3389/fenrg.2016.00002 Determination of Terpenoid Content in Pine by Organic Solvent Extraction and Fast-GC Analysis Anne E. Harman-Ware1* , Robert Sykes1 , Gary F. Peter2 and Mark Davis1 1 National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA, 2 School of Forest Resources and Conservation, University of Florida, Gainesville, FL, USA Terpenoids, naturally occurring compounds derived from isoprene units present in pine oleoresin, are a valuable source of chemicals used in solvents, fragrances, flavors, and have shown potential use as a biofuel. This paper describes a method to extract and analyze the terpenoids present in loblolly pine saplings and pine lighter wood. Various extraction solvents were tested over different times and temperatures. Samples were analyzed by pyrolysis-molecular beam mass spectrometry before and after extractions to monitor the extraction efficiency. The pyrolysis studies indicated that the optimal extraction method used a 1:1 hexane/acetone solvent system at 22°C for 1 h. Extracts from the hexane/acetone experiments were analyzed using a low thermal mass modular accelerated column heater for fast-GC/FID analysis. The most abundant terpenoids from Edited by: the pine samples were quantified, using standard curves, and included the monoter- Subba Rao Chaganti, University of Windsor, Canada penes, α- and β-pinene, camphene, and δ-carene. Sesquiterpenes analyzed included Reviewed by: caryophyllene, humulene, and α-bisabolene. Diterpenoid resin acids were quantified in Yu-Shen Cheng, derivatized extractions, including pimaric, isopimaric, levopimaric, palustric, dehydroabi- National Yunlin University of Science and Technology, Taiwan etic, abietic, and neoabietic acids.