Fig. 2.

Negative ion mode summed MS spectrum of patient P1 ovarian tissue annotated with proposed structures for N-glycans identified by PGC-LC-ESI MS/MS. N-glycans released in-solution from formalin-fixed paraffin-embedded ovarian cancer tissue (P1) using PNGaseF were reduced, de-salted and purified on a carbon column prior to porous graphitic column chromatography coupled online to an ESI-IT-MS system. The proposed glycan structures were deduced from their doubly charged negative ion monoisotopic masses [M-2H]²⁻.