Fig. 2

Monosaccharide composition of HA samples by HILIC-CAD. Authentic standards and commercially purchased HA samples were hydrolyzed by 2 M TFA for 2 h before composition analysis by the HILIC-CAD gradient method. a Represents a chromatogram of GlcNAc and GlcA standards. The degradation of GlcNAc into GlcN is evident from the chromatogram. b Is a representative chromatogram of NaCl solution. The sodium and chloride ion peaks are visible in the chromatogram. c Shows a chromatogram of a hydrolyzed HA standard. The Cl⁻, GlcNAc, GlcN, Na⁺ and GlcA peaks can be seen along with an unknown peak (**). The unknown peak is speculated to be a disaccharide repeating unit of HA. d Is a representative chromatogram of a hydrolyzed HA serum sample. The composition of d is identical to c indicating that it is an authentic product