Premium
Characterization of oxysterols by electrospray ionization tandem mass spectrometry after one‐step derivatization with dimethylglycine
Author(s) -
Jiang Xuntian,
Ory Daniel S.,
Han Xianlin
Publication year - 2006
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.2820
Subject(s) - chemistry , tandem mass spectrometry , fragmentation (computing) , electrospray ionization , derivatization , electrospray , chromatography , protonation , mass spectrometry , oxysterol , stereochemistry , combinatorial chemistry , organic chemistry , ion , computer science , operating system , biochemistry , cholesterol
We report a novel approach to derivatize the primary, secondary, and tertiary hydroxy group(s) of oxysterols with N,N ‐dimethylglycine (DMG) in the presence of both 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide and 4‐( N,N ‐dimethylamino)pyridine to yield their corresponding mono‐ or di‐DMG esters. Eight oxysterols including 7‐oxocholesterol, 5 α ,6 α ‐ and 5 β ,6 β ‐epoxycholesterols, as well as 7 α ‐, 7 β ‐, 24( S )‐, 25‐, and 27‐hydroxycholesterols, were studied. Electrospray ionization tandem mass spectrometric characterization of these singly or doubly protonated derivatives demonstrates the presence of an informative fragmentation pattern for each oxysterol derivative. Potential dissociation pathways for the production of these unique fragmentation patterns are proposed and discussed. Collectively, these informative and unique fragmentation patterns allow rapid and direct discrimination of the identities of 7 α ‐, 7 β ‐, 24( S )‐, 25‐, and 27‐hydroxycholesterol isomers, as well as 5 α ,6 α ‐ and 5 β ,6 β ‐epoxycholesterol isomers, thereby potentially providing a foundation for quantitative analysis of oxysterols in biological samples in combination with a chromatographic separation. Copyright © 2006 John Wiley & Sons, Ltd.