TABLE 1.
Tentative assignment of biochemical bands identified by FT-IR spectroscopy
| Biomolecule group | Wavelength (cm−1) | Assignment(s)a |
|---|---|---|
| Protein | 3,200 | Amide A ν(NH) |
| 3,129 | Amide B ν(NH) | |
| 3,070 | Amide B CNH | |
| 1,667 | Amide I ν(CO) coupled to δ(NH2) in-plane | |
| 1,655 | Amide I (α helix) | |
| 1,637 | Amide I (β structure) | |
| 1,550 | Amide II α helix | |
| 1,530 | Amide II, β structure | |
| 1,330 | Amide III | |
| 1,267 | Amide III (α helix) | |
| 1,250 | Amide III (β sheet) | |
| Phospholipids and lipid proteins | 2,960 | ν(CH3) membrane phospholipids |
| 2,920 | ν(CH2) membrane phospholipids | |
| 2,875 | νs(CH3) | |
| 2,850 | νs(CH2) membrane phospholipids | |
| 1,740 | ν(CO) esters | |
| 1,467 | δ(CH2) lipids and proteins | |
| 1,455 | δ(CH3) and δ(CH2) scissoring lipids and proteins | |
| 1,420 | νa(CH3) lipids and aromatics | |
| 1,397 | δ(CH3) methyl bond | |
| 1,370-1,400 | δ(COO−) and δ(CH3) lipids and proteins | |
| Phosphate and carbohydrate | 1,235 | νa(PO32−) |
| 1,170 | νa(COOC) phospholipids and/or cholesterol esters | |
| 1,150 | ν(CO) saccharides | |
| 1,054 | νs(COOC) | |
| 970 | ν(CC), ν(CN), and ν(PO32−) | |
| 935 | CC residue α helix | |
| 906 | CC stretch proline | |
| RNA and DNA | 1,710 | ν(CO) RNA (esters) |
| 1,690 | ν(CO), RNA, and DNA | |
| 1,106 | νs(PO2−) nucleic acids | |
| 1,063 | ν(CO), deoxyribose/ribose DNA, and RNA | |
| Finger print | 600-900 |