Updated project metadata. This dataset was generated to model discovery of uncommon and non-canonical PTM by agnostic analysis. Synthetic DFSAFILVEFCR peptides were obtained in three chemoforms, all with carbamidomethylated C12: 1) with unmodified phenylalanines, 2) with fluoro-F2, and 3) with fluoro-F11. Peptide composition and chemical modifications were confirmed using mass spectrometry. Peptides were analyzed in neat solvent for sequence and modification confirmation, and in the context of AML cell tryptic proteome.