Figure 5.

Differential mass labelling of the NFHQYSVEGGK peptide. A – mass spectrum of the unmodified peptide. B – mass spectrum of the same peptide modified with 4-fluorophenyl-isothiocyanate (introduced Δ m/z = 153). C – mass spectrum of the same peptide modified with 3,5-difluorophenyl-isocyanate (introduced Δ m/z = 155).