Collisional-activation tandem mass spectrometry of sodium adduct ions of methylated oligosaccharides: sequence analysis and discrimination between α-NeuAc-(2 → 3) and α-NeuAc-(2 → 6) linkages

Abstract

Collision-activated dissociation (c.a.d.) of sodium adducts of molecular ion species have been carried out on methylated β- d-Gal p-(1 → 4)-β- d-Glc pNAc-(1 → 3)-β- d-Gal p-(1 → 4)- d-Glc p ( 1), β- d-Gal p-(1 → 3)-β- d-Glc pNAc-(1 → 3)-β- d-Gal p-(1 → 4)- d- Glc p ( 2), α- d-NeuAc-(2 → 3)-β- d-Gal p-(1 → 3)-β- d-Glc pNAc-(1 → 3)-β- d-Gal p-(1 → 4)- d-Glc p ( 3), α- d-NeuAc-(2 → 6)-β- d-Gal p-(1 → 4)-β- d-Glc pNAc-(1 → 3)-β- d-Gal p-(1 → 4)- d-Glc p ( 4), and α- d-NeuAc-(2 → 6)-β- d-Gal p-(1 → 4)-β- d-Glc pNAc-(1 → 2)-α- d-Man p-(1 → 3)-β- d-Man p-(1 → 4)- d-Glc pNAc. ( 5). The numerous daughter ions reflect the sequences, clearly differentiate (1 → 3) and (1 → 4) linkages, and discriminate between α-NeuAc-(2 → 3) and α-NeuAc-(2 → 6) linkages.