the infrared spectra of hyaluronic acid ( ha ) , protein chondroitin keratan sulfate ( pcks ) , aggregates of proteoglycans ( ap ) , glucuronic acid and its potassium salt , glucosamine , galactosamine ( both as hydrochlorides ) , n-acetyl-glucosamine , n-acetyl-galactosamine , ammonium salt of n-acetyl-neuraminic acid were obtained in the region 200 -- 4000 cm-1 .
C0017718
glucosamine
C0001056
n-acetyl-glucosamine