Table 3.
Vibrational peaks and assignments of FTIR spectra of G. thoracica, H. itama, and T. binghami propolis.
| Stingless bee propolis |
Vibrational modes | ||
|---|---|---|---|
| H. itama | G. thoracica | T. binghami | |
| 3312(b) | 3466(b) | 3425(b) | νO-H of alcohols, phenols and carboxylic acids |
| 2926(s) | 2918(s) | 2920 | νN-H of amines |
| 2853(s) | 2851(s) | 2851 | νCH3, νCH2 and νCH of alkenes |
| 1693(b) | 1721(l) | 1710 | νC = O of carbonyl |
| 1603(b) | 1646(s) | 1644 | νC = C of conjugated aromatic rings |
| 1515(w) | 1538(s) | 1545(b) | δN-H of amines; νC-C aromatic ring |
| 1443(s) | 1430(b) | 1459(s) | δCH of aromatic rings |
| 1379(s) | 1383(s) | 1382 | νC-O of carboxylic acids |
| --- | 1315(s) | 1315(w) | νC-O alcohols; ωCH2 of alkenes |
| 1283(w) | 1243(w) | 1244 | νC-O phenols |
| 1221(s) | --- | 1213 | νC-O of phenols |
| 1160(w) | 1157(s) | 1160 | νC-N of amines |
| 1073(w) | 1082(s) | 1069 | νC-C aromatic rings |
| 1033(b) | 1029(s) | 1032 | νC-O of esters |
| 813(w) | 817 | --- | γCH2 of alkenes |
| 771(s) | --- | 757 | γC-H of alkenes |
| 717 | 714 | --- | γC-H of alkenes |
| 687 | --- | 667 | γO-H of alcohols and phenols |