| | Spectral zone | Peak frequency cm−1 | Chemical bonds |
| | 1,800−1,500 cm−1 | ≈1,730 cm−1 | C=O stretch (lipids, triglycerides, and alkyl-esters) | | 1,660–1,666 cm−1 | C=O stretch (amide I-proteins) | | 1,608 cm−1 | COO− antisymmetric stretch (acidic group of polygalacturonic acids) | | 1,540–1,550 cm−1 | N–H deformation; C–N stretch (amide II, proteins and lignin) | | ≈1,514 cm−1 | C=C–C (approximation of aromatic ring bonding) (sporopollenin) |
| | 1,400−1,000 cm−1 | 1,416–1,418 cm−1 | COO− symmetric stretch (acidic group of polygalacturonic acids) | | 1,440−1,450 cm−1 | CH2, CH3 deformation (acidic group of polygalacturonic acids) | | 1,318−1,321 cm−1 | (C–C, C–O) (acetylenic compounds) | | 1,255−1,257 cm−1 | C–O–H deformation; C=O stretching of phenolics (lipids and triglycerides, pectins, and carbohydrate molecule) | | 1,104–1,106 cm−1 | C–OH skeletal; C–O–C sugar ring (carbohydrate molecule) | | 1,050–1,055 cm−1 | C–O–C stretch; C–OH stretch; C–OH deformation; C–O–C deformation, pyranose, and furanose ring (carbohydrate molecule) |
| | 900−800 cm−1 | ≈920 cm−1 | C–H (β-glycosidic bond) (carbohydrate molecule) | | 830−836 cm−1 | C–O–C (α-glycosidic bond) (carbohydrate molecule) |
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