Simultaneous microanalysis of N-linked oligosaccharides in a glycoprotein using microbore graphitized carbon column liquid chromatography–mass spectrometry

We previously reported that graphitized carbon column liquid chromatography–mass spectrometry (GCC-LC–MS) is very useful for the structural analysis of carbohydrates in a glycoprotein. In this study, GCC-LC–MS was adapted for the simultaneous microanalysis of oligosaccharides. A variety of oligosaccharide alditols prepared from fetuin, ribonuclease B, and recombinant human erythropoietin were used as model oligosaccharides. The use of microbore GCC-LC–MS was found to be successful for rapid, sensitive, and simultaneous analysis of high-mannose-type, desialylated fucosyl complex-type, sialylated complex-type, and sialylated fucosyl complex-type oligosaccharide alditols. Furthermore, we demonstrate that this method is applicable to the analysis of carbohydrate heterogeneity in a glycoprotein that possesses diverse oligosaccharides. Microbore GCC-LC–MS was able to characterize high-mannose-type, hybrid-type, and complex-type oligosaccharides in tissue plasminogen activator produced from human melanoma cells in a single analysis.