Table 4.

Functional groups present in collagen type I.

Amide Structure	Amide Type	Source of the Signal	Wavenumber (cm−1)
	I	C=O stretch	1620 < ν < 1800
	II	N–H bend coupled withC–N stretch	1590 < ν < 1650
	III	N–H bend	1200 < ν < 1400
	A	N–H stretch coupled with hydrogen bond	3300 < ν < 3400