Tentative infrared bands assignment (cm–1)

Sodium alginateκ-carrageenanAssignment
3,4433,600–3,100(OH)
3,100–2,800(CH)
2,970ν(OH)
1,642δ(OH)
1,610νasymmetric (COO)
1,417νsymmetric (COO)
1,238ν(S=O)
1,258ν(C–O)
1,165ν(C–O), ν(C–C) and δ (C–C–C)
912ν(C–O–C) glycosidic bond
848/704δ(C–O–S)