JMSSJ On-line, Vol. 52 (2004) No. 2, pp. 57-62
Collision-Induced Dissociation (CID) Spectra versus Collision Energy Using a Quadrupole Ion Trap Mass Spectrometer IV:
Dissociation of Ionized Maleamide and Fumaramide
>> Full Text PDF
>> References
    Susumu TAJIMA, *a) Masaaki UBUKATA, b) and Masao FUJISHIGE a)

    *a)Chemistry and Material Science, Gunma National College of Technology (Toriba, Maebashi, Gunma 371-0845, Japan) trap mass spectrometer.1), 8), 9),b)Present address: MS Application Laboratory, Application and Research Center, JEOL, Ltd. (Musashino, Akishima, Tokyo 196-8558, Japan)
The unimolecular decompositions of the geometrical isomers maleamide (cis-NH2COCH = CHCONH2; 1, MW: 114) and fumaramide (trans-NH2COCH = CHCONH2; 2, MW: 114) have been investigated by use of collision-induced dissociation (CID) spectra versus collision energy. These ions, 1+ • and 2+ •, show as primary fragmentation channels the losses of NH2 and CONH to give the ions m/z 98 and 71, respectively, but the relative abundance of these ions is different with each other. This will be attributable to amide-amide interaction in cis-isomer. The fragment ions m/z 71 correspond to the molecular ion of acrylamide, CH2 = CHCONH2, which is formed by hydrogen atom migration from NH2 to ethylenic carbon in the molecular ions 1+ • and 2+ •, followed by CONH loss. The additional dissociation channels are observed for 2+ • , the losses CO and CONH2 to give the ions at m/z 86 and 70, respectively. These two reactions were weak for 1+ •. These ions, except for m/z 71 ion, retain the structure difference between the geometrical isomers. The [M-NH2]+ ions decompose further by the losses of H2O and CO to generate the ions at m/z 80 and 70, respectively. The former reaction for 1 is different from that for 2. This reaction accompanies with double hydrogen atom transfers, and was not described in previous report.
Key words: CID spectra versus collision energy, Geometrical isomer, Differentiation of ions, D-Labeling
[ Full Text PDF ]    [ References ]
© COPYRIGHT by The Mass Spectrometry Society of Japan. All Rights Reserved.