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Tentative identification and quantification of TAG core aldehydes as dinitrophenylhydrazones in autoxidized sunflowerseed oil using reversed‐phase HPLC with electrospray lonization MS
Author(s) -
Sjövall Olli,
Kuksis Arnis,
Kallio Heikki
Publication year - 2003
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/s11745-003-1177-7
Subject(s) - chemistry , autoxidation , chromatography , chromatography detector , high performance liquid chromatography , glyceride , aldehyde , electrospray , electrospray ionization , mass spectrometry , linseed oil , organic chemistry , catalysis , fatty acid
The molecular species of TAG core aldehydes (aldehydes still esterified to parent molecules) were detected and quantified in dietary‐quality sunflowerseed oil autoxidized for 0‐18 d at 60°C in the dark. The analyses were performed by reversed‐phase HPLC with UV (358 nm) absorption or light scattering and electrospray ionization‐MS (ESI/MS) detection following preparation of the dinitrophenylhydrazone derivatives. Aldehyde production, as estimated by UV and ESI/MS, increased gradually over the 18‐d period following a rapid initial destruction of the core aldehydes accumulated during storage of the commercial oil at 10°C for 3 mon. The contents of hydroperoxides and hydroperoxide core aldehyde combinations were estimated to account for about 5% of total TAG, quantified as area in the chromatographic trace, after 18 d of autoxidation as estimated by an evaporative light scattering detector (ELSD). The major species of core aldehydes were tentatively identified as 9‐oxononanoyl (70%)‐, 12‐oxo‐9,10‐epoxydodecenoyl (10%)‐, and 13‐oxo‐9,11‐tridecadienoyl (5%)‐containing acylglycerols, plus smaller amounts of simple and mixed chain‐length dialdehydes, and hydroxy and epoxy monoaldehyde‐containing acylglycerols (15% of total). Quantitatively, the core aldehydes made up 2–12 g/kg of oil by UV detection and 2–9 g/kg of oil by EsI/MS detection, whereas the hydroperoxides measured in the unreduced state by HPLC with ELSD were estimated at 200 g/kg after 18 d of autoxidation. The major hydroperoxides of sunflowerseed oil were as previously identified.