Table 1.

Information on the band positions within the amide I insulin detemir second derivative reference and fibril spectra.^18,19,25

Wavenumber (cm‒1)	Bioactive insulin band intensities	Fibril band intensities	Secondary structure
1694–1695	Weak	Weak	Beta sheet
1668–1681	Weak	Medium	Turns
1646–1655	Strong	Weak	Alpha helix
1640	Medium	None	Random
1627–1629	Weak	Strong	Beta sheet
1613–1614	Medium	Weak	Side chain
1593	Medium	Weak	C–C stretching from phenyl rings