Table 3.
The IR spectrum data of the four polysaccharides.
| GLP a | SCP a | DAP a | ULLP a | Characteristic Peaks |
|---|---|---|---|---|
| Wavenumber (cm−1) | ||||
| 3200–3400 | 3200–3400 | 3200–3400 | 3200–3400 | O–H stretch vibration |
| 2927.1 | - | 2891.6 | - | C–H stretch vibration |
| 1638.4 | 1598.6 | 1608.2 | 1597.0 | Asymmetric and symmetric stretching of carboxylate anions group (C=O) |
| - | 1410.4 | 1415.5 | 1411.2 | |
| - | 1247.8 | 1249.5 | 1257.4 | Stretching vibration of S–O of sulfate |
| 1150.7 | 1134.8, 1198.3 | - | 1137.7, 1103.3 | C–O stretch vibration of secondary alcohol |
| 1038.9 | 1030.0 | 1028.6 | 1032.1 | The pyranose ring and glycosidic bond C–O stretching vibrations |
| 890.7 | 881.5 | 891.0 | 882.3 | An absorption peak at 891 cm−1 indicated the presence of β-d-glucan, and 880 cm−1 attributed to the β-mannose absorption peak, with pyran group |
| - | - | 816.2 | 817.0 | |
a GLP, SCP, DAP, and ULLP are polysaccharides extracted from G. lemaneiformis, S. ceylonensisa, D. Antarctic, and Ulva lactuca L, respectively.