Fig. 1: Schematic representation of the Mass-Retention Time Fingerprinting analytical workflow.

Specific colors (yellow, blue, red, orange, and green) represent elastase-cleaved peptides. Shades of the same color represent three possible glycoforms of the same peptide, which resolve only partially by HPLC. The three workflow stages are 1 reduction/alkylation and elastase digestion. 2 Reversed phase LC–MS. 3 Database matching.