Table 2.

Methods for determining the physicochemical properties of chitin, chitosan, and COS.

Physicochemical Properties	Determination Methods
Degree of deacetylation	Potentionmetric method [17,33,34] FT-IR [25] Acid-base titration [26]
Degree of polymerization	MALDI-TOF MS [18], 1H NMR [20]
Degree of N-acetylation	MALDI-TOF MS and 1H NMR [18] HPLC-a photodiode array (PDA) [23]
Chemical structure	FT-IR [22,30,33,34] ESI-MS [31] UV [33,34]
Viscosity	A falling-ball viscometer [24]
Color tone intensity	Etereo microscope [25]
Intrinsic viscosity molecular weight	An Ubbelohde Viscometer [25,26,32,34]