An Investigation of Gaseous α-Halogenated Carbocations and Isomeric Halonium, Halenium, and Allylhalonium Ions

2003 ◽  
Vol 56 (5) ◽  
pp. 437 ◽  
Author(s):  
Robert W. Holman ◽  
Jennifer Davis ◽  
Amy Walstrom ◽  
Michelle McCombs ◽  
Gina Jackson ◽  
...  
Keyword(s):  
Gas Phase ◽  
Halogen Atom ◽  
Mass Spectrometric ◽  
Recent Theory ◽  
Tandem Mass ◽  
Carbenium Ions ◽  
Ion Formation ◽  
Tandem Mass Spectrometric ◽  
Ion Species ◽  
Halonium Ion

We investigated with tandem mass spectrometric methods (MS/MS) the nature and extent of stabilization of gas-phase alkyl, vinyl and 2-allyl carbenium ions caused by halogen participation of neighboring chlorine and bromine atoms. The extent of halogen atom stabilization is greatest for alkyl ions, followed closely by that for vinyl ions, and is significantly less for the 2-halosubstituted allyl ions. The data is consistent with bridged halonium ion formation in alkyl systems and bridged halenium ion formation in vinyl systems. Our results for the 2-chloro allyl system are in accord with an earlier NMR interpretation rather than with recent theory, indicating that a bridged allyl halonium ion species is involved.

Confirmation of Identities of Propylene and Ethylene Glycols in Anchovies by Tandem Mass Spectrometry

1993 ◽  
Vol 76 (6) ◽  
pp. 1344-1347 ◽  
Author(s):  
Jean E Matusik ◽  
Paul P Eilers ◽  
Ellen M Waldron ◽  
Steve M Conrad ◽  
James A Sphon
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Chemical Ionization ◽  
Mass Spectrometric ◽  
Tandem Mass ◽  
Human Food ◽  
Ethylene Glycols ◽  
Tandem Mass Spectrometric ◽  
Ion Species ◽  
Positive Ion

Abstract A gas chromatographic/tandem mass spectrometric (GC/MS/MS) method has been developed for confirming the identity of propylene and ethylene glycols added to bait fish for preservation. Bait fish are occasionally illegally diverted to human food use. The bait fish were extracted with methanol, the extract was centrifuged and filtered, and the filtrate was concentrated 10-fold and then analyzed by GC/MS/MS. The glycols were separated chromatographically without derivatization or preliminary cleanup. Isobutane positive ion chemical ionization was used to generate the protonated molecular ion species of each glycol. Product-ion MS/MS experiments were performed to obtain spectra to confirm the identities of propylene and ethylene glycols. The identities of these 2 compounds in anchovy extracts were successfully confirmed by this approach.

The Mechanism of 2-Furaldehyde Formation from d-Xylose Dehydration in the Gas Phase. A Tandem Mass Spectrometric Study

2013 ◽  
Vol 24 (7) ◽  
pp. 1082-1089 ◽  
Author(s):  
Andreina Ricci ◽  
Simona Piccolella ◽  
Federico Pepi ◽  
Stefania Garzoli ◽  
Pierluigi Giacomello
Keyword(s):  
Gas Phase ◽  
Mass Spectrometric Study ◽  
Mass Spectrometric ◽  
Tandem Mass ◽  
Spectrometric Study ◽  
Tandem Mass Spectrometric

Endothermic ion-molecule reactions: strategies for tandem mass spectrometric structural analyses of large biomolecules

1990 ◽  
Vol 62 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Ron. Orlando ◽  
Constance. Murphy ◽  
Catherine. Fenselau ◽  
Gordon. Hansen ◽  
Robert J. Cotter
Keyword(s):  
Mass Spectrometric ◽  
Tandem Mass ◽  
Ion Molecule Reactions ◽  
Tandem Mass Spectrometric
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