Table 1.

Summary for different sample preparation protocols and whether ¹⁵N glycan peaks can be picked.

Mix iGlycoMab with blood serum	Pre-treatment	Denaturation condition	15N glycan identified
Before denaturation and PNGase F digestion	None	60°C, 1hour	No
after digestion, before reduction	None	60°C, 1hour	Yes
after reduction, before permethylation	None	60°C, 1hour	Yes
Before denaturation and PNGase F digestion	Protein precipitation	60°C, 1hour	No
Before denaturation and PNGase F digestion	wash though 10k MWCO filter	60°C, 1hour	No
Before denaturation and PNGase F digestion	None	90°C, 20 minutes	Yes
Before denaturation and PNGase F digestion	Tryptic digestion	60°C, 1hour	Yes