Possible heterocyclic ions in the reaction zones of flames with added nitrogen or sulfur

1984 ◽  
Vol 37 (3) ◽  
pp. 511 ◽  
Author(s):  
T McAllister
Keyword(s):  
Reaction Zone ◽  
Ionization Mass ◽  
Proton Affinities ◽  
Flame Ionization ◽  
Ionization Mass Spectroscopy ◽  
Hydrogenation Reactions ◽  
Reaction Zones ◽  
Aromatic Species ◽  
Cyano Compounds ◽  
Cn Radicals

Ions of m/z 80 and 94 are observed in the reaction zone of a C6H6/N2O/H2 flame, by flame ionization/mass spectroscopy. These are confirmed, by deuteration, as protonated pyridine and aniline. These ions are also detected in the reaction zone of a CH4/N2O flame, along with ions of m/z 44, 56, 68 and 72, which, it is proposed, are formed by protonation of the heterocyclic species aziridine, dihydroazete, pyrrole and pyrrolidine. This series of N-containing ions is in keeping with the postulate that HCN is formed in flames of hydrocarbons and N-compounds, and that the associated CN radicals undergo addition and hydrogenation reactions. Cyano compounds are not, however, detected, because their proton affinities tend to be lower than that of NH3. In a C6H2/CS2/H2 flame, a series of S-containing ions are observed, beginning at m/z 97, for which the thiopyrylium structure is proposed. The detection of this stable aromatic species is in contrast to the absence of protonated thiophene. It is postulated that the active S-containing species in this flame is CS.

scholarly journals Development of a photochemical source for the production and calibration of acyl peroxynitrate compounds

2015 ◽  
Vol 8 (5) ◽  
pp. 2225-2231 ◽  
Author(s):  
P. R. Veres ◽  
J. M. Roberts
Keyword(s):  
Dynamic System ◽  
Mass Spectroscopy ◽  
Chemical Ionization ◽  
Acyl Chloride ◽  
Ionization Mass ◽  
Gas Chromatograph ◽  
Iodide Ion ◽  
Ionization Mass Spectroscopy ◽  
Subsequent Separation ◽  
Standard Production

Abstract. A dynamic system for the calibration of acyl peroxynitrate compounds (APNs) has been developed in the laboratory to reduce the difficulty, required time, and instability of laboratory-produced standards for difficult-to-synthesize APN species. In this work we present a photochemical source for the generation of APN standards: acetyl peroxynitrate (PAN), propionyl peroxynitrate (PPN), acryloyl peroxynitrate (APAN), methacryloyl peroxynitrate (MPAN), and crotonyl peroxynitrate (CPAN). APNs are generated via photolysis of a mixture of acyl chloride (RC(O)Cl) and ketone (RC(=O)R) precursor compounds in the presence of O2 and NO2. Subsequent separation by a prep-scale gas chromatograph and detection with a total NOy instrument serve to quantify the output of the APN source. Validation of the APN products was performed using iodide ion chemical ionization mass spectroscopy (I- CIMS). This method of standard production is an efficient and accurate technique for the calibration of instrumentation used to measure PAN, PPN, APAN, MPAN, and CPAN.

Multiphoton Ionization Mass Spectroscopy of Fullerenes in Methane Diffusion Flames

1994 ◽  
Vol 359 ◽  
Author(s):  
H. Hepp ◽  
K. Siegmann ◽  
K. Sattler
Keyword(s):  
Aromatic Hydrocarbons ◽  
Atmospheric Pressure ◽  
Diffusion Flames ◽  
Multiphoton Ionization ◽  
Ionization Mass ◽  
Ionization Time ◽  
Ionization Mass Spectroscopy ◽  
Polycyclic Aromatic ◽  
On Line ◽  
Methane Diffusion

ABSTRACTMultiphoton ionization time-of-flight mass spectrosocopy is used as an on-line technique to investigate polycyclic aromatic hydrocarbons (PAH) and fullerenes in atmospheric pressure flames. We have recorded height profiles of neutral PAH and fullerenes in methane/argon diffusion flames. Fullerenes ranging from C32 to at least C150 are found in a region where PAH concentration starts to decrease. Uniformity of the profiles indicates that the fullerenes do not grow from smaller to larger ones. The influence of the amount of argon additive is discussed.

scholarly journals Chemical ionization mass spectrometry (CIMS) may not measure all gas-phase sulfuric acid if base molecules are present

2010 ◽  
Vol 10 (12) ◽  
pp. 30539-30568
Author(s):  
T. Kurtén ◽  
T. Petäjä ◽  
J. Smith ◽  
I. K. Ortega ◽  
M. Sipilä ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Sulfuric Acid ◽  
Gas Phase ◽  
Chemical Ionization ◽  
Measurement Data ◽  
Ionization Mass Spectrometry ◽  
Chemical Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Proton Affinities ◽  
Reaction Thermodynamics

Abstract. The state-of-the art method for measuring atmospheric gas-phase sulfuric acid is chemical ionization mass spectrometry (CIMS) based on nitrate reagent ions. Using computed proton affinities and reaction thermodynamics for the relevant charging reactions, we show that in the presence of strong bases such as amines, which tend to cluster with the sulfuric acid molecules, a significant fraction of the total gas-phase sulfuric acid may not be measured by a CIMS instrument. If this is the case, this effect has to be taken into account in the interpretation of atmospheric sulfuric acid measurement data, as well as in intercomparison of different CIMS instruments, which likely have different susceptibilities to amine-sulfuric acid clustering.

scholarly journals FRAGMENTATION STUDIES OF D6,7-ANHIDROERITROMISIN-A BY LIQUID CHROMATOGRAPHY-MASS SPECTROSCOPY (LC-MS)

2010 ◽  
Vol 9 (3) ◽  
pp. 474-478
Author(s):  
Khairan Khairan ◽  
Umar A. Jenie ◽  
Retno S. Sudibyo
Keyword(s):  
Liquid Chromatography ◽  
Electrospray Ionization ◽  
Mass Spectroscopy ◽  
Saccharopolyspora Erythraea ◽  
Wave Number ◽  
Ionization Mass ◽  
Fragmentation Pattern ◽  
Ionization Mass Spectroscopy ◽  
Stretching Vibration ◽  
Two Peaks

Semisynthesis of D6,7-Anhydroerythromycin-A was done by biomodification technique by addition of 0.2% INH into a culture fermentation of Saccharopolyspora erythraea ATCC 11635 in medium Hutchinson. The aim of this research is to studies of fragmentation pattern from new matabolite of D6,7-Anhydroerythromycin-A by Liquid Chromatography-Mass Spectroscopy (LC-MS) and the ionization of mass spectroscopy is use by ESI (Electrospray Ionization) pattern. The FT-IR spectrometric analyzes showed a stretching vibration of C=C conjugated group at wave number 1602.7 cm-1. This C=C conjugated vibration indicated the existence of double bond between C6 and C7 (D6,7), this confirmed that isolate contained D6,7-Anhydroerythromycin-A (the possibility of D6,7 was positive). For complementation, a LC-MS (Liquid Chromatography-Mass Spectroscopy) analyzes using ESI-MS (Electrospray Ionization-Mass Spectroscopy) ionization pattern was conducted to the isolate which resulted Quassimolecular ions [M+H]+ of D7,8- and D6,7-Anhydroerythromycin-A. LC-MS spectrogram of the isolate, which gave two peaks of m/z 732.2460 and m/z 716.2522, confirmed that the m/z 732.2460 possibly was D7,8-Anhydroerythromycin-A, while the m/z 716.2502 and m/z 715.2522 possibly were D6,7-Anhydroerythromycin-A.   Keywords: isoniazid, enoyl reduction, D6,7-Anhidroeritromisin-A, fragmentation, LC-MS.

scholarly journals Fe(III)-doxycycline complexes with diimine ligands: Syntheses, characterization and biological properties

2019 ◽  
Vol 38 (1) ◽  
pp. 29
Author(s):  
Joshua A Obaleye ◽  
Olufunso Olumide Abosede
Keyword(s):  
Binding Constants ◽  
Biological Properties ◽  
Axial Position ◽  
Klebsiella Pneumonia ◽  
Ionization Mass ◽  
Polypyridyl Ligands ◽  
Diimine Ligands ◽  
Electrospray Ionization Mass Spectroscopy ◽  
Ionization Mass Spectroscopy ◽  
Ct Dna

Three new iron(III) complexes of doxycycline viz: [Fe(dox)2Cl]Cl2 (1), [Febpy(dox)Cl]Cl2 (2) and [Fephen(dox)Cl]Cl2 (3), where dox is doxycycline, bpy is 2,2ʹ-bipyridine and phen is 1,10-phenanthroline, were synthesized and characterized by elemental analysis, electronic absorption, FT-IR, and electrospray ionization mass spectroscopy. Doxycycline and the polypyridyl ligands behave as bidendate ligands; the polypyridyl ligands coordinate through the two diimine nitrogen atoms and doxycycline through enolate and diketoamide oxygen atoms of ring A in a five-coordinate system with chloride atom in the axial position. Their antibacterial and antiplasmodial activities against chloroquine-sensitive Plasmodium falciparum NF54 and their interaction with calf thymus (CT) DNA using electronic titration were investigated. The three complexes showed good activity against strains of Staphylococcus aureus and Klebsiella pneumonia. The complexes bind moderately to CT DNA with binding constants of 5.6 × 104 and 4.8 × 104 for complexes 2 and 3, respectively.

High-throughput quantification of sodium saccharin in foods by ambient flame ionization mass spectrometry

Talanta ◽  
2018 ◽  
Vol 182 ◽  
pp. 241-246 ◽  
Author(s):  
Zhongquan Li ◽  
Fang Zhang ◽  
Junbo Zhao ◽  
Xiaopan Liu ◽  
Xiuping Chen ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Throughput ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Flame Ionization ◽  
Sodium Saccharin

Homoadamantane and Adamantane Acylphloroglucinols from Hypericum hirsutum

Planta Medica ◽  
2021 ◽  
Author(s):  
Julianna Max ◽  
Jörg Heilmann
Keyword(s):  
Petroleum Ether Extract ◽  
2D Nmr ◽  
Positive Control ◽  
Ionization Mass ◽  
2D Nmr Spectroscopy ◽  
Vitro Assay ◽  
Ionization Mass Spectroscopy ◽  
Ic50 Values ◽  
Adamantane Skeleton

Abstract 1H NMR-guided fractionation of the petroleum ether extract of the aerial parts from Hypericum hirsutum yielded to the isolation of 19 polyprenylated polycyclic acylphloroglucinols. Structure elucidation based on 1D and 2D NMR spectroscopy together with high-resolution electrospray ionization mass spectroscopy revealed 14 acylphloroglucinols with a homoadamantane scaffold (1–14), while 5 further compounds showed an adamantane skeleton (15–19). Except for hookerione C (15), all isolated metabolites are hitherto unknown. While structurally-related metabolites have been isolated from other Hypericum species, it is the first report of admantan and homoadamantan type acylphloroglucinols in section Taeniocarpium Jaub. & Spach (Hypericaceae). The isolated compounds have been tested in a crystal violet-based in vitro assay on their properties to reduce the proliferation of human microvascular endothelial cells compared to hyperforin as the positive control. They showed a moderate reduction of proliferation with IC50 values in the range ~ 3 – 22 µM, with the homoadamantane-based compounds 2 and 4 being the most active. In addition, inhibition of the TNF-α-induced ICAM-1 expression was determined for 1 – 5, 7, and 10 – 12. Substances 3 and 12 reduced the ICAM-1 expression significantly (to 46.7% of control for 3, 62.3% for 12, at 50 µM).

Diode-Laser-Initiated Resonance Ionization Mass Spectroscopy of Sm I

2000 ◽  
Vol 37 (5) ◽  
pp. 697-700 ◽  
Author(s):  
Hyunmin Park ◽  
Miran Lee ◽  
E. C. Jung ◽  
Jonghoon Yi ◽  
Yongjoo Rhee ◽  
...  
Keyword(s):  
Diode Laser ◽  
Mass Spectroscopy ◽  
Resonance Ionization ◽  
Ionization Mass ◽  
Ionization Mass Spectroscopy
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