scholarly journals The infrared multiphoton dissociation of hexafluoroethane

1988 ◽  
Vol 66 (4) ◽  
pp. 609-614 ◽  
Author(s):  
Carl E. Brown ◽  
Donald R. Smith
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
High Frequency ◽  
High Sensitivity ◽  
Infrared Multiphoton Dissociation ◽  
Tunable Diode Laser ◽  
Product Analysis ◽  
Multiphoton Dissociation ◽  
First Time

The infrared multiphoton dissociation (IRMPD) of "neat" hexafluoroethane has been investigated for the first time. The stable products of photolysis are CF4, C2F4, C3F8, and C4F10. Product analysis involved tunable diode laser (TDL) and fourier transform infrared spectroscopy, as well as gas chromatography where applicable. The high sensitivity and resolution of the TDL allows for measurement of the stable products CF4 and C2F4 after irradiation by a single infrared laser pulse. The yield of CF3 radicals produced by the IRMPD of C2F6 as a function of fluence was measured via the TDL high frequency modulation technique. The role of added H2, leading to elimination of CF4 and increase of C2F4 as products, is clarified.

Review Lecture. Spectroscopy of molecular ion beams

1979 ◽  
Vol 367 (1731) ◽  
pp. 433-449 ◽  
Keyword(s):  
Mass Spectrometry ◽  
Direct Detection ◽  
High Sensitivity ◽  
Infrared Multiphoton Dissociation ◽  
Molecular Ions ◽  
Ion Beams ◽  
Indirect Methods ◽  
Molecular Ion ◽  
Multiphoton Dissociation ◽  
Laser Sources

Many important molecular ions may be formed and identified by using the techniques of mass spectrometry. The molecular ion beams formed in a mass spectrometer are not sufficiently intense for direct detection of the absorption of electromagnetic radiation, but absorption spectra can be obtained by using laser sources and indirect methods of detection. The principles underlying the indirect methods are discussed and several examples described. Under favourable conditions, well resolved spectra can be obtained with high sensitivity. Possible developments involving infrared multiphoton dissociation of ion beams are discussed.

Characterization of Oligodeoxynucleotide Fragmentation Pathways in Infrared Multiphoton Dissociation and Electron Detachment Dissociation by Fourier Transform Ion Cyclotron Double Resonance

2009 ◽  
Vol 15 (2) ◽  
pp. 293-304 ◽  
Author(s):  
Jiong Yang ◽  
Kristina Håkansson
Keyword(s):  
Fourier Transform ◽  
Bond Cleavage ◽  
Double Resonance ◽  
Infrared Multiphoton Dissociation ◽  
Electron Detachment Dissociation ◽  
Electron Detachment ◽  
Fragmentation Pathways ◽  
Ion Cyclotron ◽  
Multiphoton Dissociation ◽  
Tandem Mass Spectrometric

Infrared multiphoton dissociation (IRMPD) is a vibrational excitation tandem mass spectrometric fragmentation method valuable for sequencing of oligonucleotides. For oligodeoxynucleotides, typical product ions correspond to sequence-specific 5′ ( a-base) and their complementary 3′ w-type ions from carbon–oxygen bond cleavage at the 3′ position of the deoxyribose from which a nucleobase is lost. Such fragmentation patterns are also observed in collision activated dissociation (CAD). The CAD oligodeoxynucleotide fragmentation mechanism has been characterized in detail. By contrast, fragmentation schemes in IRMPD have not been rigorously established. In this paper, we apply, for the first time, Fourier transform ion cyclotron double resonance (DR) experiments to characterize IRMPD fragmentation pathways of oligodeoxynucleotide anions. Our results suggest that neutral base loss precedes backbone fragmentation but that T-rich oligodeoxynucleotides fragment via a different mechanism, similar to the mechanisms proposed for CAD. We also extend the DR approach to characterize intermediates in electron detachment dissociation of hexamer oligodeoxynucleotides. Here, we found that charge reduced radical precursor ions constitute major intermediates for dT6, d(GCATAC) and d(GCATGC). Furthermore, ( a/ z–T) ions ( z ions correspond to C–O bond cleavage on the other side of a backbone phosphate group as compared to the formation of a ions) mainly originate from secondary fragmentation of a/ z radical ions for the oligodeoxynucleotide dT6.

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