Fast purification of glycans and glycopeptides using silk-packed micropipette tip for matrix-assisted laser desorption/ionization-mass spectrometry and high-performance liquid chromatography-fluorescence detection analysis

A novel micropipette tip packed with a natural product generated from silk worms is introduced in this study for the specific separation and purification of glycopeptides and glycans. The enrichment and purification performances of the silk-packed micropipette tip were investigated for both glycopeptide and glycan levels. Site-specific glycosylation analysis of tryptic IgG Fc glycopeptides by MALDI-MS was achieved using a protocol containing enrichment step with the silk-packed micropipette tip. The enrichment efficiency and specificity of the silk-packed pipette tip regarding to glycopeptides and glycans was evaluated using the digests of some glycoproteins having neutral and sialylated glycopeptides and glycans. The MS and HPLC-FLD results indicate that the silk-packed micropipette tip has good adsorption capacity to glycoconjugates in HILIC enrichment mode. In addition, purification of 2-aminobenzoic acid labelled IgG, fetuin and human plasma N-glycans with silk-packed micropipette tip was performed, and thus salts (PBS), detergents (SDS, NP-40) and interfered solvents (such as DMSO etc.) were removed prior to MS and HPLC-FLD analyses.