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Topic: Chemical ionization

    Note: these results are not from the primary (high quality) database.

Patent 4220545: Ionization chamber for chemical ionization Ionization chamber for the chemical ionization of vapors of substances in ion-molecule reactions by means of ionizing primary particles and a reactance gas, having at least one inlet opening for feeding the reaction partners and at least one outlet opening for the reaction products formed in the chamber. The invention relates to an ionization chamber for the chemical ionization of vapors of substances in ion-molecule reactions by means of ionizing primary particles and a reactance gas, having at least one inlet opening for feeding the reaction partners and at least one outlet opening for the reaction products formed in the chamber. The ionization of atoms or molecules, particularly of organic substances, in ion-molecule reactions, also called chemical ionization, has, compared to the usual ionization by electronic impact, the advantage of low fragmentation of the examined substances. www.freepatentsonline.com /4220545.html

Chemical Ionization (CI) Chemical Ionization (EI) was introduced by Field and Munson (1966). As with EI, chemical ionization requires that the molecules are vaporized before ionization. When fragmentation is observed, it is frequently due to the loss of small neutral molecules (water, ammonia, acetic acid) from the protonated molecule. www.chem.harvard.edu /mass/tutorials/ci.html

Lipids, lipid analysis, Literature Survey - Atmospheric-pressure chemical-ionization mass spectrometry (APCI MS) of lipids (phospholipids, glycolipids, triacylglycerols) Byrdwell,W.C. and Neff,W.E. Dual parallel electrospray ionization and atmospheric pressure chemical ionization mass spectrometry (MS), MS/MS and MS/MS/MS for the analysis of triacylglycerols and triacylglycerol oxidation products. Neff,W.E. and Byrdwell,W.C. Characterization of model triacylglycerol (triolein, trilinolein and trilinolenin) autoxidation products via high-performance liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry. Breithaupt,D.E. Identification and quantification of astaxanthin esters in shrimp (Pandalus borealis) and in a microalga (Haematococcus pluvialis) by liquid chromatography mass spectrometry using negative ion atmospheric pressure chemical ionization. www.lipidlibrary.co.uk /lit_surv/apci_ms.html

non-chemical water treatment - Copper Silver Ionization - Ionization Ionization models are manufactured, calibrated and tested to deliver proper Copper and Silver concentrations based on our clients' water usage. Our "E" series ionizators are modular and represent 48 different models to accommodate all jobs of any size. www.waterionization.com /about.html

Instrumentation and Ionization Methods Tutorial Chemical Ionization (CI) is applied to similar samples; it is used to enhance the abundance of the molecular ion. Electron-capture (sometimes called negative ion chemical ionization or NICI) is used for molecules containing halogens, NO CN, etc, and it usually requires that the analyte be derivatized to contain highly electron-capturing moieties (e.g., fluorine atoms or nitrobenzyl groups). Electron ionization (EI) is widely used in mass spectrometry for relatively volatile samples that are insensitive to heat and have relatively low molecular weight. www.chemistry.wustl.edu /~msf/ionmethd.html

Inproteo: Publications McGuire, K. Jallad, D. Ben-Amotz and R. Hammers, "Chemical Mapping of Elemental Sulfur on Pyrite and Arsenopyrite Surfaces using Near-Infrared Raman Imaging Microscopy," Appl. Augusti, F. Carazza R. Augusti, W. Tao and R. Cooks, “Rapid quantitative chiral analysis of sugars by electrospray ionization tandem mass spectrometry using modified amino acids as chiral reference compounds” Anal. Mechref and M.V. Novotny, “Structural Investigations of Glycoconjugates at High Sensitivity” Chemical Reviews 102(2) 321-370 (2002). www.inproteo.com /propub.html

RMS Conference 2003 Abstract Detail An electron-impact ionization mass spectrometer has been rebuilt and successfully modified to allow chemical ionization at pressures of ca. The new detection system offers specific simultaneous detection of both VOCs with chemical ionization ( via charge transfer) allowing detection of the parent molecular ions. The chemical-ionization mass spectrometer (CIMS) will be used initially to study the reactions of the nitrate radical with propene and 1-butene. www.metlink.org /conf2003/detail.php?recordID=246

separationsNOW.com - resource for chromatography, HPLC, electrophoresis, genomics and more In the chemical ionization mode of operation, the 4000 GC/MS delivers superior adduct ion formation in positive CI, remarkable selectivity in negative CI, and can be coupled with MS/MS detection. Internal Ionization: Based on the field-proven Saturn 2000 series GC/MS, the Varian 4000 system achieves the industry standard for sensitivity, both in full-scan electron ionization (EI) and positive chemical ionization (PCI) operation. Hybrid Chemical Ionization : The hybrid configuration offers a truly novel approach to positive and negative chemical ionization. www.separationsnow.com /basehtml/SepH/1,1353,0-1-1-0-0-news_detail-0-1090,00.html

Chemical Ionization Mass Spectrometry Chemical ionization mass spectra of 13 classes of compounds are discussed in detail to illustrate the influence of different functional groups on the spectra observed. Chemical Ionization Mass Spectrometry, 2nd Edition will be a valuable reference for anyone interested in mass spectrometry and gaseous ion chemistry in general. Other chapters discuss such topics as reagent ion systems within the context of the thermochemistry and kinetics of the ionization process, including reactions and the type of information obtained; isotopic exchange reactions; stereochemical effects in chemical ionization; and reactive ion/molecule collisions in quadrupole cells. www.arsmedica.com /cr/cr-1402.html

Chemical Ionization (CI) Chemical reagent gas added to modified EI ion source www.sou.edu /chem/ch425/MassSpec-Chapter20/sld010.htm

Chemical Glossary Ionization is caused by a gain or loss of electrons. An element whose electrons are loosely held (first and second columns of chart) surrenders its outer electron(s) to an element with high ionization energy (that therefore has a high electron affinity). Elements from opposite sides of the chart have very different ionization energies, so that one atom is strong enough to rip off electrons from the other. www.petrik.com /PUBLIC/library/misc/chemical_glossary.htm

Chemical Ionization Chemical ionization technique uses virtually the same ion source device as in electron impact, except, CI uses tight ion source, and reagent gas. For organic chemists, Chemical Ionization (CI) is especially useful technique when no molecular ion is observed in EI mass spectrum, and also in the case of confirming the mass to charge ratio of the molecular ion. Molecular ions observed in negative ion chemical ionization mass spectra are usually M www.public.iastate.edu /~kamel/ci.html

Patent 4377745: Mass spectrometer for chemical ionization, electron impact ionization and mass spectrometry/mass spectrometry operation Each chemical ionization operation mode is followed by a venting operation mode during which the gaseous content of the ion source box 62 is rapidly vented out through the controlling device and into the ion source section 22 and pumped away subsequently. For a chemical ionization mass spectrometer which is interfaced with a gas chromatograph the peak resolution achieved by the gas chromatograph is often deteriorated to some degree because of an unavoidable sample build-up which results from insufficient source conductance. It is difficult, if not impossible, for known spectrometers to treat in both a chemical ionization mode and in an electron impact ionization mode each of a plurality of sample materials sequentially entering the ionization region from the gas chromatograph. www.freepatentsonline.com /4377745.html

1200 GCMS Chemical Ionization Chemical Ionization using the 1200 GC/MS The Varian 1200 GC/MS offers both EI and Chemical Ionization (CI) as standard with the instrument, using both positive and negative CI techniques. Townsend Discharge ionization is offered as an option for the petroleum and petrochemical industries. It is a very useful technique for the characterization of hydrocarbons in the petroleum industry as it can be used to determine the concentrations of n-paraffins, isoparaffins, cycloparaffins, and aromatics, and their carbon number distributions. www.varianinc.com /cgi-bin/nav?varinc/docs/products/chrom/gcms/gcms_tqCI&cid=975JINLJQLJKOGLMOOJOM

Analytical Spectroscopy Section Currently, there are eight ion trap mass spectrometers in the group equipped with a wide variety of ionization techniques, including electron ionization, chemical ionization, electrospray, matrix-assisted laser desorption, and atmospheric sampling glow discharge. Laser based measurements include techniques for detection and manipulation of single molecules in microparticles, diagnostics for and studies of chemical vapor deposition processes, nonlinear optical probes of surfaces, resonance ionization mass spectrometry for isotopic analysis, real-time chemical characterization of aerosol particles, and application of diode lasers to chemical measurement problems. Similarly, ionization techniques, such as electrospray, matrix-assisted laser desorption and glow discharge, are being investigated to expand the fundamental understanding of the techniques and to expand the applicability of mass spectrometry to a broader range of compounds and applications. www.ornl.gov /sci/casd/AS_Section.html

Chemical Sciences: Ionization Constants of Acids and Bases Chemical Sciences: Ionization Constants of Acids and Bases The ionization direction in aqueous solution is the direction of forming hydrogen ions or hydroxide ions without regard to any other ions formed or removed in the reaction. Aqueous ionization constants of acids and bases are always written in this way regardless ofthe actual charge on the acid or base. www.ualberta.ca /~jplambec/che/p101/p01133.htm

Ionization Methods in Mass Spectrometry Chemical ionization uses ion-molecule reactions to produce ions from the analyte. The chemical ionization process begins when a reagent gas such as methane, isobutane, or ammonia is ionized by electron impact. Although ionization and desorption/desolvation are usually separate processes, the term " ionization method " is commonly used to refer to both ionization and desorption (or desolvation) methods. www.jeol.com /ms/docs/ionize.html

Hunter College Mass Spectrometry Facility Chemical ionization is a softer ionization technique that is used for molecules that undergo excessive fragmentation in electron impact ionization. Our instrument is equipped with two ionization sources, electron impact and chemical ionization. Samples can be run using electron impact ionization as well as positive and negative chemical ionization mode (using methane or ammonia). patsy.hunter.cuny.edu /facilities/masss.html

Chemical Ionization Mass Spectrometry Chemical Ionization Mass Spectrometry-Based Measurements of HO and RO During TRACE-P product is detected first by ionization through a proton transfer reaction with, followed by introduction into a vacuum system with ion optics, differential pumping, quadrupole mass filter and channel electron multiplier for ion counting. Lower detection limits with better precision are possible with appropriate averaging. www-gte.larc.nasa.gov /trace/TP_Cantrell.htm

Chemical Supplier - Laboratory Equipment - ScienceLab.com Sciencelab.com, the low price chemical supplier for laboratory equipment, specialty chemicals and science educational products. We offer thousands of products ranging from chemicals and reagents, pH meters, digital scales, microscopes, refractometers, laboratory glassware, chemistry supplies and more. The NEW ATAGO PAL-1 Handheld Refractometer is exceptionally small in size allowing for portability of use indoors or out. www.ScienceLab.com

Mass spectrometric ionization methods Chemical Ionization is an ionization technique similar to the classical EI but the knowledge and results of ion-molecule reactions are exploited. Atmospheric pressure chemical ionization is a relative of ESI. Electron impact ionization is the classical ionization technique in mass spectrometry. www.ivv.fhg.de /ms/ms-ionization.html

Chemical Principles of Electrospray Ionization Mass Spectroscopy Electrospray Ionization uses an electric field to produce a spray of fine droplets, which is used to create the spectrum. In many applications of mass spectrometry it is necessary to obtain a mass spectrum from a sample dissolved in a solvent. A new source for ESI mass Spec, where four LC sources are connected to one ESI-time-of-flight Mass Spectrometer. analytical.chem.wisc.edu /524class/Folders/Heiden/electrosprayB.html

OAMG - Publications Zeeb, D.J., Nelson, B.C., Albert, K., and Dalluge, J.J., Separation and Identification of Twelve Catechins in Tea Using Liquid Chromatography/Atmospheric Pressure Chemical Ionization-Mass Spectrometry, Anal. Nelson, B.C., The Connection Between Biological and Chemical Standard Reference Materials and the National Health Care System, Chemical and Engineering News, 79, 288 (2001). Wise, S.A. and Jacob, J., Chapter 3.4 Certification of Organic Substances, In: Reference Materials for Chemical Analysis - Certification, Availability and Proper Usage, Stoeppler, M., Wolf, W.R., and Jenks, P.J. (eds.), Wiley-VCH, Weinheim, Germany, 83-110 (2001). www.cstl.nist.gov /nist839/839.02/publications.html

Untitled Document Zhao, X. and Yinon, J.: Characterization and origin identification of 2,4,6-trinitrotoluene through its by-product isomers by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry. Zhao, X. and Yinon, J.: Identification of nitrate ester explosives by liquid chromatography-electrospray ionization and atmospheric pressure chemical ionization mass spectrometry. Zhao, X. and Yinon, J.: Forensic identification of explosive oxidizers by electrospray ionization mass spectrometry. ncfs.ucf.edu /phys_evd.html

Thermo Electron Corporation - - Analysis of Explosives by Chemical Ionization GC/MS This application provides a method for analyzing a number of explosive compounds, including precursors and residues, in negative chemical ionization using gas chromatography-mass spectrometry. Analysis of Explosives by Chemical Ionization GC/MS By determining extremely low levels of compounds, the Finnigan TRACE DSQ GC/MS exhibits high performance by minimizing extraction time and resources in the analysis of explosives. The method proves to be successful in providing accurate and rapid identification of explosive residues using fast GC techniques. www.ethermo.com /com/cda/resources/resources_detail/1,2166,111554,00.html

N95-078 Sponsor/Monitor: ONR - Chemical Ionization Mass Spectrometric Instrument for Multiple Species Measurements from a Remotely Piloted Vehicle - Aerodyne Research, Inc - Phase III Success Story Also, the chemical ionization flow reactor needs to be optimized for marine boundary layer conditions, with high humidity and atmospheric pressure at the flow tube inlet. Chemical Ionization Mass Spectrometric Instrument for Multiple Species Measurements from a Remotely Piloted Vehicle The chemical ionization scheme for the acid gases and several of the precursors has been demonstrated to have high selectivity, using the CO3- ion generated from O2 and CO2. www.navysbir.brtrc.com /successstories/Aerodyne2P3.html

Ionization Graph Ionization energy is not as useful for predicting the chemical activity of nonmetals and metalloids. Ionization Energy is the amount of attraction an atom has for its own electrons. This information is particularly useful in predicting how each metallic element will behave chemically. www.sciencebyjones.com /ionization_graph.htm

Agilent - Search Detail Positive chemical ionization provides a high degree of selective ionization for the phthalates, primarily producing spectra in which the protonated molecule (M+1) is the base peak. A New Approach to the Analysis of Phthalate Esters by GC/MS Abstract: A new instrumental method for the determination of 29 phthalate esters, including six recently banned in baby toys by the European Union, using positive chemical ionization and retention-time locking is described. The combination of positive chemical ionization and retention-time locking makes the method rugged, durable, and applicable to wide variety of matrices. www.chem.agilent.com /scripts/LiteraturePDF.asp?iWHID=21653

Hepatic and Serum Bile Acid Compositions in Patients with Biliary Atresia: A Microanalysis Using Gas Chromatography-Mass Spectrometry with Negative Ion Chemical Ionization Detection Hepatic and serum bile acids in five patients with biliary atresia were preoperatively determined by microanalysis using gas chromatography-mass spectrometry with negative ion chemical ionization detection. Hepatic and Serum Bile Acid Compositions in Patients with Biliary Atresia: A Microanalysis Using Gas Chromatography-Mass Spectrometry with Negative Ion Chemical Ionization Detection journal.med.tohoku.ac.jp /1854/185401.html

Dimethyl Ether Chemical Ionization Of Arylalkylamines (ResearchIndex) Abstract: Introduction Dimethyl ether, when used in chemical ionization mass spectrometry, produces the CH 3 OCH 2 + cation, m/z 45, which behaves like an ambident electrophile 1. 1 Dimethyl Ether Chemical Ionization Mass Spectrometry (context) - Burrows - 1996 The reactions of various types of compounds with DME have been studied 1,2 and reviewed 3 by several authors. citeseer.ist.psu.edu /411955.html

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