Carbohydrate release from picomole quantities of glycoprotein and characterisation of glycans by high-performance liquid chromatography and mass spectrometry.

Samples of 5 to 20 microg of human IgG were subjected to dithiothreitol treatment to reduce disulphide bridges, followed by tryptic digestion. Glycans released from the tryptic peptide mixture by PNGase F digestion were then derivatised with 2-aminoacridone. Labelled oligosaccharides were separated by normal-phase high-performance liquid chromatography and individual components were collected for matrix-assisted laser desorption ionization time-of-flight and electrospray mass spectrometric analysis.