Semi-quantitative analysis of serum and cerebrospinal fluid transferrin glycoforms by top-down liquid chromatography mass spectrometry.

Detection of β-2 transferrin in body fluid could help identify cerebrospinal fluid (CSF) leakage. The most common method, isoelectric focusing, was qualitative and could not provide detailed N-glycan structural information. We presented an alternative method using top-down liquid chromatography-time of flight mass spectrometry (LC-TOF MS). After immunoaffinity enrichment, fluid transferrin glycoforms were analyzed by a high-resolution LC-TOF MS, and the N-glycan structure predicted by accurate mass. The performance was validated with imprecision at 15%, with a cut-off of 0.04 for β-2 transferrin to tetrasialotransferrin ratio to confirm the presence of CSF in fluid samples.