Dephosphorylation of intact glycoprotein to greatly improve digestion efficiency coupled with matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometric analysis.

•Dephosphorylation of intact glycoprotein to greatly improve digestion efficiency.•The enrichment efficiency for multisialylated glycopeptides were enhanced using phosphoric acid solution as elution buffer.•Validation was made by analyzing human serum α2-macroglobulin and transferrin.