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A new solution for an old problem: the regiochemical distribution of the acyl chains in galactolipids can be established by electrospray ionization tandem mass spectrometry
Author(s) -
Guella Graziano,
Frassanito Rita,
Mancini Ines
Publication year - 2003
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.1142
Subject(s) - chemistry , degree of unsaturation , electrospray ionization , chromatography , tandem mass spectrometry , electrospray , mass spectrometry
Electrospray ionization‐quadrupole ion trap mass spectrometry (ESI‐QITMS), either in positive‐ or in negative‐ion mode, has been used to establish the chemical structures (chain length, degree of unsaturation, positional distribution) of the fatty acids attached to the primary ( sn ‐1) and secondary ( sn ‐2) hydroxyl groups of the glycerol moiety of natural monogalactosyl‐ (MGDG) and digalactosyldiacylglycerols (DGDG), isolated from the freshwater dinoflagellate Glenodinium sanguineum and from a marine diatom belonging to the genus Chaetoceros . Fragmentation by collision‐induced dissociation of a single component in MGDG and DGDG mixtures, separated by high‐performance liquid chromatography (HPLC) and detected on‐line by tandem positive‐ion ESI‐MS, leads to a clear‐cut determination of the positional distribution of the sn ‐glycerol‐bound fatty acyl chains. Reversed‐phase liquid chromatography allowed a partial resolution of the component mixture before ESI‐MS/MS analysis. These results were validated by comparison with ESI‐MS data obtained for the sn ‐2 lysoglyceroglycolipids synthesized via regiospecific enzymatic hydrolysis of the corresponding diacylglycerols by Rhizopus arrhizus lipase. Copyright © 2003 John Wiley & Sons, Ltd.