What absorbs at 1408 cm⁻¹ in an FTIR spectrum?
A band near 1408 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Réponse rapide
A band near 1408 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Attributions possibles de groupes fonctionnels
| Groupe fonctionnel | Faits à l＇appui | Sources citées | Confiance maximale |
|---|---|---|---|
| Alkyl C-H | 11 | 10 | 1,0 |
| Amide | 9 | 9 | 1,0 |
| Acetate | 8 | 8 | 1,0 |
| Methacrylate | 7 | 7 | 1,0 |
| Carbonyl (C=O) | 6 | 6 | 1,0 |
| Methoxy (OCH3) | 5 | 5 | 1,0 |
| N h | 5 | 5 | 1,0 |
| Carboxyl (COOH) | 5 | 4 | 1,0 |
| Secondary amine | 4 | 4 | 1,0 |
| C-O single bond | 4 | 4 | 1,0 |
| Aromatic ring | 4 | 3 | 1,0 |
| C n single bond | 3 | 3 | 1,0 |
| Amino acid | 3 | 3 | 1,0 |
| Ketone | 3 | 3 | 1,0 |
| Ester | 3 | 3 | 1,0 |
| Methyl | 2 | 2 | 1,0 |
| Ring structure | 2 | 2 | 1,0 |
| Lipid | 2 | 2 | 1,0 |
| C c single bond | 2 | 2 | 1,0 |
| S eq o | 1 | 1 | 1,0 |
| Sulfonyl | 1 | 1 | 1,0 |
| Alkene (C=C) | 1 | 1 | 1,0 |
| Acetyl | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
| Protein | 1 | 1 | 1,0 |
| Carbonate | 1 | 1 | 1,0 |
| Protein beta sheet | 1 | 1 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| Fluorine (C-F) | 1 | 1 | 0,9 |
| Boron nitrogen | 1 | 0 | 1,0 |
Le classement reflète les preuves bibliographiques accumulées, et non une règle faisant autorité. Confirmez toujours dans le contexte de votre échantillon.
Matériaux possibles
| Matériel | Pics de support | Groupes chevauchants | Sources citées |
|---|---|---|---|
| PET | 1408, 800, 1205 | Methacrylate, Acetate, Alkyl C-H | 1 |
| TiO2 | 1408, 1700, 1093 | Alkyl C-H, Methacrylate, Acetate | 1 |
| Al2O3 | 1408, 1722, 1383 | Methacrylate, Acetate, Alkyl C-H | 1 |
Les matériaux sont affichés uniquement lorsque le même ensemble de littérature soutient cette bande et au moins un pic caractéristique supplémentaire.
Logique du spectre
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 1408 cm⁻¹ is usually not enough for material identification by itself.
Utilisation réelle
Ce type de requête est courant dans l＇identification des polymères, le criblage des plastiques inconnus, le dépannage du contrôle qualité, la vérification des matériaux recyclés et l＇examen de l＇attribution des pics appuyée par la littérature.
Erreurs courantes
- Traiter une bande isolée comme preuve d＇un matériau sans vérifier au moins un ou deux pics de support.
- Ignorer le chevauchement : plusieurs groupes fonctionnels peuvent contribuer près du même nombre d＇onde.
- Sauter la validation lorsque des additifs, des mélanges, l＇oxydation ou la contamination peuvent déformer le spectre.
Conseil de vérification
Lorsque l＇ambiguïté persiste, validez l＇hypothèse avec DSC, GC-MS ou TGA, en particulier pour les mélanges, les échantillons dégradés et les polymères chargés.
Bibliographie derrière ces attributions
-
Alkyl C-H confiance 1,0
“Among the more intense bands, we observe in the IR SE spectra the characteristic bands corresponding to the vibration modes of the trans C-O stretch (~976 cm-1), the ester C-C, C-O stretch (~1024 cm-1), the ethylene glycol CH2 wagging mode”
Laskarakis 等 - 2004 - A Spectroscopic Ellipsometry study of PET membrane DOI: 10.1002/masy.200450109 -
Amide confiance 1,0
“The maximum of 73.1% of antiindicates asymmetric O-H stretching, 1637.7 oxidation activity was indicated by EPsC at 1000 µg/mL but cm-1 represents the Amide I band, and 1408.08 represents”
Lavania 等 - 2023 - Anatomizing extracellular polymer of Calothrix des DOI: 10.14719/pst.2615 -
Carbonyl (C=O) confiance 1,0
“The peak at 1408 is due to the cm-1 symmetric stretching of carbonyl group.”
Structural, optical, morphological and thermal properties of TiO2–Al and TiO2–Al2O3 composite powders by ball milling DOI: 10.1016/j.physleta.2017.02.053 -
Acetate confiance 1,0
“Compared with P, the spectra of the EP showed the appearance of cm-1, cm-1,1408 cm-1, 1598 which were represented C=O stretching vibration, strong bands at 1743 C=O asymmetric stretching vibration and O-H deformation vibration respectively.”
Ouyang 等 - 2012 - Adsorption of Cu (II) from aqueous single metal so DOI: 10.4028/www.scientific.net/AMR.535-537.1601 -
confiance 1,0
“According to the spectra illustrated in Fig.3, besides the CO interference band 2 cm-1, cm-1, near 2350 the bands near 1408 and 871 which correspond to amino acids and 1,2,4-three substituted benzene,”
Xia 等 - 2015 - Removal of Natural Organic Matter by Forward Osmos DOI: 10.1007/s40242-015-4374-1 -
Carbonyl (C=O) confiance 1,0
“The FTIR spectrum of the blend membrane showed new peaks at 1669 cm-1 and 1408 cm-1, corresponding to the carbonyl C=O stretching vibration and the O-H bending vibration of the carboxyl group, respec-”
Preparation and Characterization of Polymer Membranes Impregnated with Carbon Nanotubes for Olive Mill Wastewater DOI: 10.3390/polym14030457 -
Amide confiance 1,0
“The carbonyl absorption band at 1735 cm-1 27, suggested the presence of an acrylic-based emulsion whereas the presence of the amide stretching at 1408”
Chemically stable Au nanorods as probes for sensitive surface enhanced scattering (SERS) analysis of blue BIC ballpoint pens DOI: 10.1063/1.4997132 -
Amino acid confiance 1,0
“COOperenne are slightly higher (65 and 71%, Table 4) compared at 1236 amino acids, as illustrated by the cm-1, to the classification results of approach 1 (46 and 64%, stretching mode at 1408 and carbohydrates, the latter Table 2).”
Discrimination of grass pollen of different species by FTIR spectroscopy of individual pollen grains DOI: 10.1007/s00216-020-02628-2
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