Photoionization mass spectrometer studies of gas phase ozone-olefin reactions

1973 ◽  
Vol 95 (23) ◽  
pp. 7592-7599 ◽  
Author(s):  
R. Atkinson ◽  
B. J. Finlayson ◽  
J. N. Pitts
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer

The gas phase reactivity of the dimethylchloronium ion with alkylbenzenes

1981 ◽  
Vol 59 (15) ◽  
pp. 2412-2416 ◽  
Author(s):  
John A. Stone ◽  
Margaret S. Lin ◽  
Jeffrey Varah
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Aromatic Hydrocarbons ◽  
Relative Rate ◽  
Ion Source ◽  
Nucleophilic Displacement ◽  
Rate Of Reaction ◽  
Displacement Reactions ◽  
Bonded Complexes

The reactivity of the dimethylchloronium ion with a series of aromatic hydrocarbons has been studied in a high pressure mass spectrometer ion source using the technique of reactant ion monitoring. Benzene is unreactive but all others, from toluene to mesitylene, react by CH3+ transfer to yield σ-bonded complexes. The relative rate of reaction increases with increasing exothermicity in line with current theories of nucleophilic displacement reactions.

Analysis of chlorinated hydrocarbons in gas phase using a portable membrane inlet mass spectrometer

2016 ◽  
Vol 8 (36) ◽  
pp. 6607-6615 ◽  
Author(s):  
Stamatios Giannoukos ◽  
Boris Brkić ◽  
Stephen Taylor
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer ◽  
Gaseous Phase ◽  
Chlorinated Hydrocarbons ◽  
Volatile Chlorinated Hydrocarbons ◽  
First Time

A compact portable membrane inlet mass spectrometer (MIMS) has been used for the first time to detect and monitor, both qualitatively and quantitatively, volatile chlorinated hydrocarbons in the gaseous phase.

scholarly journals Ruthenium trisbipyridine as a candidate for gas-phase spectroscopic studies in a Fourier transform mass spectrometer

2004 ◽  
Vol 18 (2) ◽  
pp. 387-396 ◽  
Author(s):  
Jill R. Scott ◽  
Jason E. Ham ◽  
Bill Durham ◽  
Paul L. Tremblay
Keyword(s):  
Fourier Transform ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Rate Constant ◽  
Optical Detection ◽  
Sinapinic Acid ◽  
Spectroscopic Studies ◽  
Fluorescence Lifetimes ◽  
Fourier Transform Mass Spectrometer

Metal polypyridines are excellent candidates for gas-phase optical experiments where their intrinsic properties can be studied without complications due to the presence of solvent. The fluorescence lifetimes of [Ru(bpy)3]1+trapped in an optical detection cell within a Fourier transform mass spectrometer were obtained using matrix-assisted laser desorption/ionization to generate the ions with either 2,5-dihydroxybenzoic acid (DHB) or sinapinic acid (SA) as matrix. All transients acquired, whether using DHB or SA for ion generation, were best described as approximately exponential decays. The rate constant for transients derived using DHB as matrix was 4×107s−1, while the rate constant using SA was 1×107s−1. Some suggestions of multiple exponential decay were evident although limited by the quality of the signals. Photodissociation experiments revealed that [Ru(bpy)3]1+generated using DHB can decompose to [Ru(bpy)2]1+, whereas ions generated using SA showed no decomposition. Comparison of the mass spectra with the fluorescence lifetimes illustrates the promise of incorporating optical detection with trapped ion mass spectrometry techniques.

scholarly journals Evaluation of the chemical composition of gas- and particle-phase products of aromatic oxidation

2020 ◽  
Vol 20 (16) ◽  
pp. 9783-9803
Author(s):  
Archit Mehra ◽  
Yuwei Wang ◽  
Jordan E. Krechmer ◽  
Andrew Lambe ◽  
Francesca Majluf ◽  
...  
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer ◽  
Urban Areas ◽  
Minor Component ◽  
Proton Transfer Reaction ◽  
Chemical Mechanism ◽  
Particle Phase ◽  
Experimental Conditions ◽  
Radical Oxidation ◽  
Product Ions

Abstract. Aromatic volatile organic compounds (VOCs) are key anthropogenic pollutants emitted to the atmosphere and are important for both ozone and secondary organic aerosol (SOA) formation in urban areas. Recent studies have indicated that aromatic hydrocarbons may follow previously unknown oxidation chemistry pathways, including autoxidation that can lead to the formation of highly oxidised products. In this study we evaluate the gas- and particle-phase ions measured by online mass spectrometry during the hydroxyl radical oxidation of substituted C9-aromatic isomers (1,3,5-trimethylbenzene, 1,2,4-trimethylbenzene, propylbenzene and isopropylbenzene) and a substituted polyaromatic hydrocarbon (1-methylnaphthalene) under low- and medium-NOx conditions. A time-of-flight chemical ionisation mass spectrometer (ToF-CIMS) with iodide–anion ionisation was used with a filter inlet for gases and aerosols (FIGAERO) for the detection of products in the particle phase, while a Vocus proton-transfer-reaction mass spectrometer (Vocus-PTR-MS) was used for the detection of products in the gas phase. The signal of product ions observed in the mass spectra were compared for the different precursors and experimental conditions. The majority of mass spectral product signal in both the gas and particle phases comes from ions which are common to all precursors, though signal distributions are distinct for different VOCs. Gas- and particle-phase composition are distinct from one another. Ions corresponding to products contained in the near-explicit gas phase Master Chemical Mechanism (MCM version 3.3.1) are utilised as a benchmark of current scientific understanding, and a comparison of these with observations shows that the MCM is missing a range of highly oxidised products from its mechanism. In the particle phase, the bulk of the product signal from all precursors comes from ring scission ions, a large proportion of which are more oxidised than previously reported and have undergone further oxidation to form highly oxygenated organic molecules (HOMs). Under the perturbation of OH oxidation with increased NOx, the contribution of HOM-ion signals to the particle-phase signal remains elevated for more substituted aromatic precursors. Up to 43 % of product signal comes from ring-retaining ions including HOMs; this is most important for the more substituted aromatics. Unique products are a minor component in these systems, and many of the dominant ions have ion formulae concurrent with other systems, highlighting the challenges in utilising marker ions for SOA.

scholarly journals Photoproducts of the Photodynamic Therapy Agent Verteporfin Identified via Laser Interfaced Mass Spectrometry

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5280
Author(s):  
Chris Furlan ◽  
Jacob A. Berenbeim ◽  
Caroline E. H. Dessent
Keyword(s):  
Mass Spectrometry ◽  
Photodynamic Therapy ◽  
Macular Degeneration ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Red Light ◽  
Solution Phase ◽  
Collision Induced Dissociation ◽  
Free Base ◽  
New Information

Verteporfin, a free base benzoporphyrin derivative monoacid ring A, is a photosensitizing drug for photodynamic therapy (PDT) used in the treatment of the wet form of macular degeneration and activated by red light of 689 nm. Here, we present the first direct study of its photofragmentation channels in the gas phase, conducted using a laser interfaced mass spectrometer across a broad photoexcitation range from 250 to 790 nm. The photofragmentation channels are compared with the collision-induced dissociation (CID) products revealing similar dissociation pathways characterized by the loss of the carboxyl and ester groups. Complementary solution-phase photolysis experiments indicate that photobleaching occurs in verteporfin in acetonitrile; a notable conclusion, as photoinduced activity in Verteporfin was not thought to occur in homogenous solvent conditions. These results provide unique new information on the thermal break-down products and photoproducts of this light-triggered drug.

ChemInform Abstract: PHOTOIONIZATION MASS SPECTROMETER STUDIES OF GAS PHASE OZONE-OLEFIN REACTIONS

1974 ◽  
Vol 5 (4) ◽  
pp. no-no
Author(s):  
R. ATKINSON ◽  
B. J. FINLAYSON ◽  
J. N. JUN. PITTS
Keyword(s):  
Gas Phase ◽  
Mass Spectrometer

Strukur und Reaktivität von Al2Cp*+ in der Gasphase. Ein experimenteller Beitrag zur Problematik der Aluminium-Aluminium- Doppelbindung / Structure and Reactivity of Al2Cp*+ in the Gas Phase. Experiments on the Problematic Nature of the Aluminum-Aluminum-Multiple Bond

2004 ◽  
Vol 59 (11-12) ◽  
pp. 1512-1518 ◽  
Author(s):  
K. Koch ◽  
H. Schnöckel
Keyword(s):  
Double Bond ◽  
Gas Phase ◽  
Quantum Chemical Calculations ◽  
Mass Spectrometer ◽  
Quantum Chemical ◽  
Multiple Bond ◽  
New Approach ◽  
Existence And Stability ◽  
Ft Icr

The cation Al2Cp*+ descending from the tetrahedral Al4Cp*4 Cluster after using LDI as ionisation method in an FT-ICR mass spectrometer reacts with Cl2 in the gas phase. The investigation of this reaction together with quantum chemical calculations gives a new approach to the question of existence and stability of an aluminum-aluminum double bond.

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