Monosaccharide composition analysis of glycoproteins by isotope-tag method and capillary LC/ESI-MS

AimTo develop a rapid and sensitive method for monosaccharide composition analysis. MethodsGlycoprotein was first hydrolyzed to monosaccharides, which were subsequently reacetylated (amino monosaccharides), tagged with 2-aminopyridine and then separated and monitored in selected ion mode by CapGCC-LC/MS. The use of tetradeuterium labeled-aminopyridyl-monosaccharides prepared by tagging monosacahrides with hexadeuterium labeled 2-aminopyridine as internal standards improved the linearity and reproducibility in quantification. ResultsThis method was successfully applied to monosaccharide composition analysis of model glycoproteins, fetuin and erythropoietin down to 1 pmol monosaccharides. ConclusionThis method has been shown to be highly sensitive and is applicable to monosaccharide composition analysis of glycoproteins.