TY - JOUR
T1 - Structural studies on ceramides as lithiated adducts by low energy collisional-activated dissociation tandem mass spectrometry with electrospray ionization
AU - Hsu, Fong Fu
AU - Turk, John
AU - Stewart, Mary E.
AU - Downing, Donald T.
N1 - Funding Information:
This research was supported by U.S. Public Health Service grants P41-RR-00954, R37-DK-34388, P60-DK-20579, and P01-HL-57-278 and grant 996003 from the Juvenile Diabetes Foundation.
PY - 2002/6
Y1 - 2002/6
N2 - We applied electrospray ionization (ESI) tandem quadrupole mass spectrometry to establish the fragmentation pathways of ceramides under low energy collisional-activated dissociation (CAD) by studying more than thirty compounds in nine subclasses. The product-ion spectra of the [M + Li]+ ions of ceramides contain abundant fragment ions that identify the fatty acyl substituent and the long-chain base (LCB) of the molecules, and thus, the structure of ceramides can be easily determined. Fragment ions specific to each ceramide subclasses are also observed. These feature ions permit differentiation among different ceramide subclasses. The ion series arising from the classical C-C bond cleavages that were reported in the fast-atom bombardment (FAB)-high energy tandem mass spectrometry is not observable; however, the product-ion spectra contain multiple fragment ions informative for structural characterization and isomer identification. We also investigated the tandem mass spectra of the fragment ions generated by in-source CAD (pseudo-MS3) and of the deuterium-labeling molecular species obtained by H/D exchange to support the ion structure assignments and the proposed fragmentation pathways that lead to the ion formation.
AB - We applied electrospray ionization (ESI) tandem quadrupole mass spectrometry to establish the fragmentation pathways of ceramides under low energy collisional-activated dissociation (CAD) by studying more than thirty compounds in nine subclasses. The product-ion spectra of the [M + Li]+ ions of ceramides contain abundant fragment ions that identify the fatty acyl substituent and the long-chain base (LCB) of the molecules, and thus, the structure of ceramides can be easily determined. Fragment ions specific to each ceramide subclasses are also observed. These feature ions permit differentiation among different ceramide subclasses. The ion series arising from the classical C-C bond cleavages that were reported in the fast-atom bombardment (FAB)-high energy tandem mass spectrometry is not observable; however, the product-ion spectra contain multiple fragment ions informative for structural characterization and isomer identification. We also investigated the tandem mass spectra of the fragment ions generated by in-source CAD (pseudo-MS3) and of the deuterium-labeling molecular species obtained by H/D exchange to support the ion structure assignments and the proposed fragmentation pathways that lead to the ion formation.
UR - http://www.scopus.com/inward/record.url?scp=0036615735&partnerID=8YFLogxK
U2 - 10.1016/S1044-0305(02)00362-8
DO - 10.1016/S1044-0305(02)00362-8
M3 - Article
C2 - 12056568
AN - SCOPUS:0036615735
SN - 1044-0305
VL - 13
SP - 680
EP - 695
JO - Journal of the American Society for Mass Spectrometry
JF - Journal of the American Society for Mass Spectrometry
IS - 6
ER -