TY - JOUR
T1 - Structural determination of glycosphingolipids as lithiated adducts by electrospray ionization mass spectrometry using low-energy collisional-activated dissociation on a triple stage quadrupole instrument
AU - Hsu, Fong Fu
AU - Turk, John
N1 - Funding Information:
This research was supported by US Public Health Service Grants P41-RR-00954, R37-DK-34388, P60-DK-20579, and P01-HL-57-278 and a grant (no. 996003) from the Juvenile Diabetes Foundation. We appreciate the excellent technical support from Alan Borher.
PY - 2001
Y1 - 2001
N2 - Structural characterization of glycosphingolipids as their lithiated adducts using low-energy collisional-activated dissociation (CAD) tandem mass spectrometry with electrospray ionization (ESI) is described. The tandem mass spectra contain abundant fragment ions reflecting the long chain base (LCB), fatty acid, and the sugar constituent of the molecule and permit unequivocal identification of cerebrosides, di-, trihexosyl ceramides and globosides. The major fragmentation pathways arise from loss of the sugar moiety to yield a lithiated ceramide ion, which undergoes further fragmentation to form multiple fragment ions that confirm the structures of the fatty acid and LCB. The mechanisms for the ion formation and the possible configuration of the fragment ions, resulting from CAD of the lithiated molecular ions ([M + Li]+) of monoglycosylceramides are proposed. The mechanisms were supported by CAD and source CAD tandem mass spectra of various cerebrosides and of their analogous molecules prepared by H-D exchange. Constant neutral loss and precursor ion scannings to identify galactosylceramides with sphingosine or sphinganine LCB subclasses, and with specific N-2-hydroxyl fatty acid subclass in mixtures are also demonstrated.
AB - Structural characterization of glycosphingolipids as their lithiated adducts using low-energy collisional-activated dissociation (CAD) tandem mass spectrometry with electrospray ionization (ESI) is described. The tandem mass spectra contain abundant fragment ions reflecting the long chain base (LCB), fatty acid, and the sugar constituent of the molecule and permit unequivocal identification of cerebrosides, di-, trihexosyl ceramides and globosides. The major fragmentation pathways arise from loss of the sugar moiety to yield a lithiated ceramide ion, which undergoes further fragmentation to form multiple fragment ions that confirm the structures of the fatty acid and LCB. The mechanisms for the ion formation and the possible configuration of the fragment ions, resulting from CAD of the lithiated molecular ions ([M + Li]+) of monoglycosylceramides are proposed. The mechanisms were supported by CAD and source CAD tandem mass spectra of various cerebrosides and of their analogous molecules prepared by H-D exchange. Constant neutral loss and precursor ion scannings to identify galactosylceramides with sphingosine or sphinganine LCB subclasses, and with specific N-2-hydroxyl fatty acid subclass in mixtures are also demonstrated.
UR - http://www.scopus.com/inward/record.url?scp=0035566770&partnerID=8YFLogxK
U2 - 10.1016/S1044-0305(00)00194-X
DO - 10.1016/S1044-0305(00)00194-X
M3 - Article
C2 - 11142362
AN - SCOPUS:0035566770
SN - 1044-0305
VL - 12
SP - 61
EP - 79
JO - Journal of the American Society for Mass Spectrometry
JF - Journal of the American Society for Mass Spectrometry
IS - 1
ER -