The complete kit includes all reagents to release, enrich, label and purify O-glycans for HPLC and LC-MS analysis. The kit adopts a unique O-glycan releasing method using a high reactive amine and an organic superbase, which yields high recovery and less degradation (peeling) of released O-glycans. Applications include characterization of O-glycosylation of recombinant glycoproteins in upstream R&D, quality control and process control. It is also suited for O-glycan biomarker discovery in biological samples such as mucins, serum and exosome, and O-glycan analysis of functional foods such as dairy products.