High-sensitivity capillary electrophoresis-electrospray ionization quadrupole ion trap time-of-flight mass spectrometry (CE-ESI-QIT-TOF MS) was developed to structurally characterize four kinds of pyridylaminated (PA) oligosaccharides, i.e., lactose (Lac)-PA, globotriose (Gb3)-PA, globotetraose (Gb4)-PA, and IV3 αGalNAc-Gb 4 (Forssman antigen)-PA, derived from neutral glycosphingolipids. The CE-MS system included the head-column field-amplified sample stacking (HC-FASS) method for effective sample injection into a capillary column in CE, a sheathless interface between CE and a mass spectrometer, and MS and tandem MS (MS2) measurements with narrow mass range repeated high-speed switching. The total sensitivity of the developed CE-MS system was about 20 000 times higher than that of the conventional CE-MS system consisting of pressure injection, a sheath-flow interface, and a wide mass range measurement. The MS and MS2 spectra of the four PA-oligosaccharides at a concentration of 25 amol/μL in mixtures (each 250 amol/10 μL in a tube) clearly showed protonated molecular ions ([M + H]+) and the fragment ions responsible for the sequential elimination of saccharides. The developed CE-MS system is a powerful method for the structural characterization of glycosphingolipids extracted from very small amounts of biological materials and could be extended to the structural characterization of oligosaccharides derived from glycoproteins.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry