Repetitively sampled time-of-flight mass spectrometry for gas-phase kinetics studies

1999 ◽  
Vol 70 (8) ◽  
pp. 3259-3264 ◽  
Author(s):  
Christopher Fockenberg ◽  
Herbert J. Bernstein ◽  
Gregory E. Hall ◽  
James T. Muckerman ◽  
Jack M. Preses ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Time Of Flight ◽  
Gas Phase Kinetics ◽  
Kinetics Studies ◽  
Flight Mass Spectrometry

scholarly journals The elusive cyclotriphosphazene molecule and its Dewar benzene–type valence isomer (P3N3)

2020 ◽  
Vol 6 (30) ◽  
pp. eaba6934 ◽  
Author(s):  
Cheng Zhu ◽  
André K. Eckhardt ◽  
Alexandre Bergantini ◽  
Santosh K. Singh ◽  
Peter R. Schreiner ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Ionizing Radiation ◽  
Gas Phase ◽  
Chemical Bonding ◽  
Building Block ◽  
Time Of Flight ◽  
Flight Mass Spectrometry ◽  
Molecular Building Block ◽  
Phosphorus Chemistry

Although the chemistry of phosphorus and nitrogen has fascinated chemists for more than 350 years, the Hückel aromatic cyclotriphosphazene (P3N3, 2) molecule—a key molecular building block in phosphorus chemistry—has remained elusive. Here, we report a facile, versatile pathway producing cyclotriphosphazene and its Dewar benzene–type isomer (P3N3, 5) in ammonia-phosphine ices at 5 K exposed to ionizing radiation. Both isomers were detected in the gas phase upon sublimation via photoionization reflectron time-of-flight mass spectrometry and discriminated via isomer-selective photochemistry. Our findings provide a fundamental framework to explore the preparation of inorganic, isovalent species of benzene (C6H6) by formally replacing the C─H moieties alternatingly through phosphorus and nitrogen atoms, thus advancing our perception of the chemical bonding of phosphorus systems.

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry of Dextran and Dextrin Derivatives

2003 ◽  
Vol 9 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Sajid Bashir ◽  
Peter J. Derrick ◽  
Peter Critchley ◽  
Paul J. Gates ◽  
James Staunton
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Time Of Flight ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Desorption Ionization ◽  
Flight Mass Spectrometry ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

Application of matrix-assisted laser desorption/ionization (MALDI) to the analysis of dextran and dextrin derivatives, specifically glucose saccharides, by time-of-flight (TOF) mass spectrometry is reported. MALDI-TOF analysis was carried out on alpha-, beta-and gamma-cyclodextrin, two O-methylated beta-cyclodextrins of differing degrees of substitution (DS) and dextrans (a linear glucose saccharide), as pure and doped solutions and as mixtures of two or more of these analytes. Doping was carried out with trace amounts of inorganic salts. The purpose of the analysis of the cyclodextrins was to determine whether they would form inclusion complexes with the various added cations, or whether less specific cation addition/exchange was occurring either prior to desorption or in the gas phase.

scholarly journals Technical Note: Gas Phase Pesticide Measurement Using Iodide Ionization Time-of-Flight Mass Spectrometry

2017 ◽  
Author(s):  
Trey Murschell ◽  
S. Ryan Fulgham ◽  
Delphine K. Farmer
Keyword(s):  
Mass Spectrometry ◽  
Relative Humidity ◽  
Gas Phase ◽  
Time Of Flight ◽  
Field Measurements ◽  
Technical Note ◽  
Analyte Molecule ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
Oxidation Chemistry

Abstract. Volatilization and subsequent processing in the atmosphere is an important environmental pathway for the transport and chemical fate of pesticides. However, these processes remain a particularly poorly understood component of pesticide lifecycles due to analytical challenges. Most pesticide measurements require long (hours to days) sampling times coupled with off-line analysis, inhibiting observation of meteorologically driven events or investigation of rapid oxidation chemistry. Here, we present chemical ionization time-of-flight mass spectrometry with iodide reagent ions as a fast and sensitive measurement of four current-use pesticides. These semi-volatile pesticides were calibrated with injections of solutions onto a filter and subsequently volatilized to generate gas phase analytes. Trifluralin and atrazine are detected as iodide-molecule adducts, while permethrin and metolachlor are detected as adducts between iodide and fragments of the parent analyte molecule. Limits of detection (1 second) are 0.37, 0.67, 0.56, and 1.1 µg/m3 for gas phase trifluralin, metolachlor, atrazine and permethrin, respectively. The sensitivities of trifluralin and metolachlor depend on relative humidity, changing as much as 70 % and 59 %, respectively, as relative humidity of the sample air varies from 0 to 80 %. This measurement approach is thus appropriate for laboratory experiments and potentially near-source field measurements.

scholarly journals Identification of a prismatic P3N3 molecule formed from electron irradiated phosphine-nitrogen ices

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cheng Zhu ◽  
André K. Eckhardt ◽  
Sankhabrata Chandra ◽  
Andrew M. Turner ◽  
Peter R. Schreiner ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Chemical Bonding ◽  
Time Of Flight ◽  
Synthetic Chemistry ◽  
Energetic Electrons ◽  
Flight Mass Spectrometry ◽  
Cage Molecules ◽  
Fundamental Understanding ◽  
Photochemical Processing

AbstractPolyhedral nitrogen containing molecules such as prismatic P3N3 - a hitherto elusive isovalent species of prismane (C6H6) - have attracted particular attention from the theoretical, physical, and synthetic chemistry communities. Here we report on the preparation of prismatic P3N3 [1,2,3-triaza-4,5,6-triphosphatetracyclo[2.2.0.02,6.03,5]hexane] by exposing phosphine (PH3) and nitrogen (N2) ice mixtures to energetic electrons. Prismatic P3N3 was detected in the gas phase and discriminated from its isomers utilizing isomer selective, tunable soft photoionization reflectron time-of-flight mass spectrometry during sublimation of the ices along with an isomer-selective photochemical processing converting prismatic P3N3 to 1,2,4-triaza-3,5,6-triphosphabicyclo[2.2.0]hexa-2,5-diene (P3N3). In prismatic P3N3, the P–P, P–N, and N–N bonds are lengthened compared to those in, e.g., diphosphine (P2H4), di-anthracene stabilized phosphorus mononitride (PN), and hydrazine (N2H4), by typically 0.03–0.10 Å.  These findings advance our fundamental understanding of the chemical bonding of poly-nitrogen and poly-phosphorus systems and reveal a versatile pathway to produce exotic, ring-strained cage molecules.

Sign in / Sign up

Export Citation Format

Share Document