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The unusual fragmentation of long‐chain feruloyl esters under negative ion electrospray conditions
Author(s) -
Schmidt Jürgen,
Kuck Dietmar,
Franke Katrin,
Sultani Haider,
Laub Annegret,
Wessjohann Ludger A.
Publication year - 2019
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.4357
Subject(s) - chemistry , fragmentation (computing) , radical , mass spectrometry , dissociation (chemistry) , collision induced dissociation , ion , alkyl , orbitrap , electrospray , tandem mass spectrometry , medicinal chemistry , organic chemistry , chromatography , computer science , operating system
Long‐chain ferulic acid esters, such as eicosyl ferulate ( 1 ), show a complex and analytically valuable fragmentation behavior under negative ion electrospay collision‐induced dissociation ((−)‐ESI‐CID) mass spectrometry, as studied by use of a high‐resolution (Orbitrap) mass spectrometer. In a strong contrast to the very simple fragmentation of the [M + H] + ion, which is discussed briefly, the deprotonated molecule, [M – H] − , exhibits a rich secondary fragmentation chemistry. It first loses a methyl radical (MS 2 ) and the ortho ‐quinoid [M – H – Me] ‐• radical anion thus formed then dissociates by loss of an extended series of neutral radicals, C n H 2n + 1 • ( n = 0–16) from the long alkyl chain, in competition with the expulsion of CO and CO 2 (MS 3 ). The further fragmentation (MS 4 ) of the [M – H – Me – C 3 H 7 ] − ion, discussed as an example, and the highly specific losses of alkyl radicals from the [M – H – Me – CO] ‐• and [M – H – Me – CO 2 ] ‐• ions provide some mechanistic and structural insights.