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7743545 
Journal Article 
Identification of fatty acid steryl esters in margarine and corn using direct flow injection ESI-MSn ion trap-mass spectrometry 
Hailat, I; Helleur, R 
2014 
Yes 
International Journal of Mass Spectrometry
ISSN: 1387-3806 
362 
1 
24-31 
English 
WOS:000335112800004 
An approach for identification of steryl esters using flow injection ESI-MS2 and ESI-MS3 ion trap mass spectrometry has been developed. Sterols and other lipids extracted from samples of margarine and corn using hexane were subjected to solid phase extraction. The steryl ester fraction was eluted with hexane:diethyl ether (98:2, v/v). In ESI-MS experiments fatty acid steryl esters were easily detected as ammoniated adducts [M+NH 4]+ using ammonium acetate as dopant. Steryl esters including molecular isomers could be identified using ESI-QIT MS2 by the facile ester cleavage whereby the charge resides with the steryl moiety. For positive confirmation of the sterol group, ESI-QIT MS3 was carried out on the intact steryl fragmentation cation. The resulting CID spectra of the steryl cation were found to be unique and similar to those from APCI-QIT MS 2 CID of free sterol standards. All major steryl esters were identified in both margarine (12 esters) and corn (7 esters) extracts. Based on the ion intensity of the ESI-MS spectra the major steryl esters in margarine were: β-sitosteryl stearate, β-sitosteryl oleate, β-sitosteryl linoleate, campesteryl stearate and campesteryl linoleate. In corn they were: β-sitosteryl oleate, campesteryl stearate, campesteryl oleate and stigmasteryl linoleate. This method can be very useful for rapid and complete identification of fatty acid steryl esters extracted from other biological samples. © 2014 Elsevier B.V. All rights reserved. 
Steryl esters; ESI-QIT MS2; ESI-QIT MS3; Margarine; Corn; Ammonium adduct solid phase extraction