Fig. 4. (A) Time-dependent intensity changes measured at the A13 isotope peak maximum overlapped with the kinetics of the main β-sheet peak at 1620 cm^–1. (B) Kinetics of the L12A13 hIAPP measured at 1560 cm^–1 and 1571 cm^–1 compared to the main β-sheet peak at 1620 cm^–1 (right). The intensity changes of the single label overlap perfectly with that of the main band, whereas the L12A13 shows more complicated kinetics.