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Structural Characterization of α,β‐Unsaturated Aldehydes by GC/MS is Dependent upon Ionization Method
Author(s) -
Long Eric K.,
Smoliakova Irina,
Honzatko Ales,
Picklo Matthew J.
Publication year - 2008
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-008-3199-9
Subject(s) - characterization (materials science) , lipidology , chemistry , gas chromatography–mass spectrometry , chromatography , ionization , organic chemistry , computational chemistry , clinical chemistry , mass spectrometry , materials science , nanotechnology , biochemistry , ion
α,β‐unsaturated aldehydes are toxic products of lipid peroxidation. Detection and characterization of these aldehydes is important in many human disease states as well as in the food industry. Our study shows that electron ionization‐mass spectrometry (EI‐MS) and positive‐ion chemical ionization‐mass spectrometry (PICI‐MS), but not electron capture negative ionization‐mass spectrometry (ECNI‐MS), can be used to detect the C4‐hydroxylation state of α,β‐unsaturated aldehydes derivatized with pentafluorobenzyl hydroxylamine alone. EI‐MS and PICI‐MS spectra of 4‐hydroxy‐2‐alkenals contained a fragment with m / z 252, whereas spectra of 2‐alkenals contained a fragment with m / z 250. These fragments are consistent with fragmentation between C3 and C4 with transfer of two hydrogens from C4 and the C4 hydroxyl group in the case of 4‐hydroxy‐2‐alkenals. In addition, EI‐MS and PICI‐MS were able to distinguish 4‐hydroxy‐2‐alkenals and 2‐alkenals from 4‐keto‐2‐alkenals and 4‐hydroxyalkanals. On the other hand, ECNI‐MS provided complex spectra regarding C4‐hydroxylation state. Furthermore, the syn ‐ and anti ‐configurations of PFB‐oximes had different resultant spectra using ECNI‐MS, but not with EI‐MS or PICI‐MS. These data indicate that EI‐MS and PICI‐MS are more amenable for structural analysis of α,β‐unsaturated aldehydes than ECNI‐MS.