| Wavenumber (cm-1) | Group | Ref. |
| 3327-3330 | O-H stretching (hydrogen bond) | Chen et al., 2016; Fan et al., 2012; Pandey, 1999 |
| 2893-2898 | C-H stretching | Chen et al., 2016; Fan et al., 2012; Pandey, 1999 |
| 1632-1639 | O-H bending of absorbed water, conjugated C=O | Chen et al., 2016; Pandey, 1999 |
| 1600 | Asymmetric stretching of the carboxylate groups and O-H bedning of the absorbed water | Qu et al., 2021 |
| 1428 | CH2 symmetric bending | Chen et al., 2016; Fan et al., 2012 |
| 1367-1368 | C-H deformation | Chen et al., 2016; Pandey, 1999 |
| 1333-1334 | O-H in-plane deforamtion | Pandey, 1999 |
| 1314-1316 | CH2 bending | Chen et al., 2016; Fan et al., 2012; Pandey, 1999 |
| 1203 | O-H deformation | Pandey, 1999 |
| 1157-1160 | C-O-C asymmeric stretching | Chen et al., 2016; Pandey, 1999 |
| 1102-1105 | β-glycosidic ether linkages (C-O-C) from wagging, deformation and twisting of anhydro-glucopyranose ring | Chen et al., 2016 |
| 1050-1051 | C-O-C pyranose ring skeleton | Chen et al., 2016 |
| 1020-1028 | C-O stretch | Pandey, 1999 |
| 895-897 | Glucose ring stretch,C1-H deformation | Pandey, 1999 |