The digestion method was optimized to reduce sample preparation induced modifications while producing high sequence coverage . The sequence coverage map of the GLP-Fc fusion DS obtained using in-solution tryptic digestion is shown in Supplementary Figure where full sequence coverage was attained for the GLP analogue, Fc region and peptide linker. A list of CQAs were detected and identified, and a targeted peptide workbook was generated according to the parameters described in SecNon 2.5. Those modificaNons with relaNve abundances over 0.1% were included in the pepNde workbook (Table ), which consisted of N-glycosylation, deamidation, succinimide formation, glycation, oxidation, and N-terminal clipping.