Written inRead online
|Statement||Elizabeth A. Stemmler, Ronald A. Hites.|
|Contributions||Hites, R. A.|
|LC Classifications||TD193 .S74 1988|
|The Physical Object|
|Pagination||xvii, 390 p. :|
|Number of Pages||390|
|LC Control Number||88000168|
Download Electron capture negative ion mass spectra of environmental contaminants and related compounds
Electron capture negative ion mass spectra of environmental contaminants and related compounds. New York: VCH Publishers, © (OCoLC) Document Type: Book: All Authors / Contributors: Elizabeth A Stemmler; R A Hites.
Electron capture mass spectrometry of organic environmental contaminants. Mass Spectrometry Reviews13 (3), The electron capture negative ion mass spectra of 2,6-dinitroaniline and 2,4-dinitrophenol herbicides and related nitrobenzene derivatives.
of organic compounds. Mass Spectrometry Reviews5 (4), https://doi Cited by: Relationship of moleculated radical anion abundance and calculated lowest unoccupied molecular orbital energies for polychlorinated dibenzofurans and dibenzodioxins in electron capture negative ion mass spectrometry: Evidence for negative metastable ions.
Biological Mass Spectrometry17 (1), Cited by: Differences in the electron capture negative ion mass spectra of environmentally related organic compounds acquired on a VG triple quadruple mass spectrometer and on an HP B gas chromatography/mass spectrometry system were investigated with respect to the ion formation process.
Neither ion source temperature nor pressure was. The primary objective of this book is to present a concise description of the experimental and theoretical procedures developed to determine fundamental energetic and kinetic properties of electron.
Organic Mass Spectrometry Vol Issue 2. Article. Electron capture negative ion and positive ion chemical ionization mass spectrometry of polychlorinated phenoxyanisoles. Jo‐Anne B. Campbell. Environmental Health Sciences Center and Department of Agricultural Chemistry, Oregon State University, Corvallis, OregonUSA.
Several new components of technical chlordane were discovered using electron capture, negative ionization gas chromatographic mass spectrometry. These compounds have 10–12 chlorines and are produced by the condensation of three cyclopentadiene molecules.
The most abundant compound has a molecular weight of and has the elemental. Electron Capture Negative Ion Mass Spectra of Environmental Contam- inants and Related Compounds. New York, NY: VCH Publishers. USGS (United States Geological Survey) Stemmler EA, Hites RA () Electron capture negative ion mass spectra of environmental contaminants and related compounds.
VCH, New York Google Scholar Stephanou E, Giger W () Persistent organic chemicals in sewage effluents 2. Calibration substances for negative ion chemical ionization mass spectrometry † Andries P.
Bruins State University, Department of Pharmacy, A. Deusinglaan 2, AW Groningen, The Netherlands. Metal ions form adducts with varying numbers of substrates to give characteristic ESI+ ions. In this poster, the accurate mass of elements, organic solvents and all potential contaminant ions observed in mass spectrometry are listed in the tables below to help troubleshoot potential contamination in LC-MS systems.
Solvents FormulaAccurate Mass. Secondary electron capture by (-methyl benzoate)tricarbonylchromium yields a molecular anion which undergoes decarbonylation and further loss of three CO groups; in addition, Cr ions have been identified in the 70 eV negative ion mass spectrum of this compound.
To analyze these compounds by gas chromatographic mass spectrometry, it is important to understand the mass spectra of these compounds using various ionization modes. This paper is a systematic overview of the electron impact (EI), electron capture negative ionization (ECNI) and positive chemical ionization (PCI) mass spectra of Selected Positive and Negative Ions in the Mass Spectra for molecule ions and many dissociative ions of a number of compounds studied so far.
This method particularly for electron-capture processes. The 0-ion from 00 (A.P.= ev)  provided a. Electron Capture Negative Ion Mass Spectra of Environmental Contaminants and Related Compounds by Stemmler, Elizabeth A and a great selection of related books, art and collectibles available now at appendix 2.
electron capture negative ion mass spectrometry of 1,2,3,4-tetrachlorodibenzofuran references appendix 3. ion-molecule interactions in electron capture negative ion mass spectrometry of octachlorodibenzofuran references appendix 4.
miscellaneous figures Mass spectrometry - Mass spectrometry - Negative ions: Discussions of the above methods have assumed that the ionization process removes one or more electrons from the atom or molecule to produce a positive ion.
Negative ions are formed by many of these same methods as well and can be useful in mass spectrometry. The accelerating voltages of the source and the direction of analyzing. The ion source produces ions either by electron ejection, electron capture, cationization, deprotonation, or the transfer of a charged molecule from the condensed to the gas phase.
MALDI and ESI have had a profound effect on mass spectrometry because they generate charged intact biomolecules into the gas phase. The ions formed by FAB were adducts to the molecule, where the adducts could be protons, sodium ions, potassium ions or ammonium ions.
A variation of FAB was replacement of the atom beam with a beam of ions, typically cesium ions, which was called secondary ion mass spectrometry (SIMS). Buy Electron Capture Negative Ion Mass Spectra of Environmental Contaminants by Elizabeth A. Stemmler, Ronald A. Hites from Waterstones today. Click and Collect from your local Waterstones or get FREE UK delivery on orders over £ The mass spectrum is run under a vacuum to prevent the presence of anything other than the ions being tested.
Not all ions will hit the detector, but the magnetic field strength can be altered to ensure that all the ion streams passing through the magnetic field can be detected. This property provides a high potential for negative ion formation through electron capture thus naturally translating to selective detection using negative ion chemical ionization mass spectrometry (NCI-MS).
This paper investigates the potential of using gas chromatography (GC) with NCI-MS for the detection of SF 6. Lewis acid–base interactions between SiF 4 and a wide range of molecular negative ions are reported here for the first time. The molecular anions include those formed by simple electron attachment to p-benzoquinone, benzophenone, nitrobenzene, and 21 substituted nitrobenzenes and also include the o- and p-nitrophenoxy measurements performed by pulsed electron-beam.
GC, in combination with electron capture negative ion mass spectrometry (ECNI), is a versatile tool for the determination of trace amounts of brominated compounds in environmental samples [ dissociative electron capture in the ion source when the instrument is operated under methane chemical ionization (CI) conditions.
Thus, the technique produces a transient ionic species that can be detected as a molecular anion of a compound or as a dissociated ion of that species produced by dissociative electron capture.
Stemmlerand R. Hites, "The Electron Capture Negative Ion Mass Spectra of 2,6- Dinitroaniline and 2,4-Dinitrophenol Herbicides and Related Nitrobenzene Derivatives", Biomedical and Environmental Mass Spectrometry, 14, (). Nontarget analysis and identification of unknown polyhalogenated compounds is important in acquiring a thorough picture of the present pollution status as well as for identifying emerging environmental problems.
Such analyses usually require the application of electron ionization mass spectrometry because the resulting mass spectra frequently allow for compound identification. Title: Electron-Capture Mass Spectrometry: A Powerful Tool in Biomedical Trace Level Analysis VOLUME: 11 ISSUE: 12 Author(s):H.
Leis, G. Fauler, G. Rechberger and W. Windischhofer Affiliation:Department of Analytical Biochemistry and Mass Spectrometry, Auenbruggerpl AGraz, Austria Keywords:resonance electron capture, mass spectrometry, negative ion.
Chemical ionization (CI) is a soft ionization technique used in mass spectrometry. This was first introduced by Burnaby Munson and Frank H.
Field in This technique is a branch of gaseous ion-molecule chemistry. Reagent gas molecules are ionized by electron ionization, which subsequently react with analyte molecules in the gas phase in order to achieve ionization. EI mass spectra, in most of cases, contain intense fragment ion peaks and much less intense molecular ion peak.
When the molecular ion peak is not observed in the mass spectrum, chemical ionization can be used in order to get molecular ion information. One helpful rule for determining whether an ion is a molecular ion is the Nitrogen Rule.
(7) NEGATIVE ION PEAK In addition to positive ions, negative ions may be formed from electron bombardment of sample. These results due to the capture of electron by a molecule during collision of molecules.
These are not observed with the usual mass spectrometer unless some modifications are made. These are generally ignored during studies. Experimental data on mass spectra of negative ions [1, 2, 3,4]] are fragmentary and incomplete as compared with the extensive volume of research on positive ions.
There are three different mechanisms by which negative ions can be formed by electron collision. Ion pair formation XY + e-7X++ Y-+e.
Resonance attachment XY +e-7XY. Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron process thereby changes a nuclear proton to a neutron and simultaneously causes the emission of an electron neutrino.
Using a mass spectrum to find relative formula mass. The formation of molecular ions. When the vaporised organic sample passes into the ionisation chamber of a mass spectrometer, it is bombarded by a stream of electrons.
These electrons have a high enough energy to knock an electron off an organic molecule to form a positive ion. The reverse process can produce negative ions. Transferring the proton to the gas molecule can, in some cases, produce the negative ion (M-H).
Chemical Ionization (CI) is sometimes used for compounds with chemistry similar to those analyzed by EI to enhance the abundance or appearance of the molecular ion in favor of significant fragmentation. Mass Spectra of Prostaglandins and Related Products (Advances in Prostaglandin, Thromboxane, and Leukotriene Research) (Vol 18) by Pace-Asciak, Cecil Robert and a great selection of related books, art and collectibles available now at Unknown-2 includes compounds identified by the NIST library as chloropropylate along with four compounds hypothesized to be TCPMOH based on spectral similarity.
However, due to the absence of molecular ions or larger fragments in their mass spectra, we assigned these compounds to an unknown category. mass-spectrometry of alkylbenzenes and related-compounds gas-phase ion chemistry of alkylbenzene radical cations: 2: 78 fresenius zeitschrift fur analytische chemie (5): binnemann p; jahr d application of mass-spectrometry in the control of food and consumer articles 0: 3 6.
Electron Capture With the electron capture ionization method, a net charge of 1- is achieved with the absorption or capture of and electron.
E.g.: Molecules with high electron affinity, such as halogenated compounds. 21 ION SOURCE Ionization of the organic compound is the primary step in obtaining the mass spectrum.
Figure The Nitrogen Rule - The mass spectrum of N,N-dimethyl-ethanamine illustrates the presence of an odd molecular ion and even fragments. Spectra from the NIST/EPA/NIH Mass Spectral Library. Reprinted with permission from NIST.
This rule is a result of nitrogen’s unique property. Nitrogen has an. Addition of an electron (electron capture) to the neutral molecule yields a negative radical ion M − [1, 17–19]. The ease of electron removal from the molecule depends on its nature, n > π > σ. Molecule ionisation energy ranges from 8 to 12 eV; for electrons, the commonly used one is 70 eV, providing maximum ionisation efficiency.positive-ion mass spectrometry.
Negative ions can be produced by a number of processes. Resonance electr on captur e refers to the capture of an electron by a neutral molecule to produce a molecular anion. The electron en - ergy is very low, and the speciÞc ener gy required for electron capture depends on the molecular structure of the analyte.Chemical compound - Chemical compound - Mass spectrometry: Mass spectrometry differs from the types of spectroscopy previously discussed because the molecular information that the technique provides does not depend on absorption of electromagnetic radiation.
In a mass spectrometer, molecules are converted to charged fragments called ions, which are then separated according to their masses.