Convenient and rapid analysis of linkage isomers of fucose-containing oligosaccharides by matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS) was used to analyze three pyridylamino (PA)-fucosyloligosaccharides isolated from human milk: lacto-N-fucopentaose (LNFP) I [Fucalpha1-2Galbeta1-3GlcNAcbeta1-3Galbeta1-4Glc-PA], LNFP II [Galbeta1-3(Fucalpha1-4)GlcNAcbeta1-3Galbeta1-4Glc-PA], and LNFP III [Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-3Galbeta1-4Glc-PA]. These oligosaccharides are linkage isomers. MALDI-QIT-TOF MS provides MS(n) spectra, which we used to characterize these PA-oligosaccharides. MS/MS/MS analysis of the non-reducing end tri-saccharide ions generated by MS/MS was able to distinguish these oligosaccharide isomers. The MALDI-QIT-TOF MS is a very convenient and rapid method, therefore, it would be useful for high throughput structural analyses of various types of pyridylaminated oligosaccharide isomers.