What absorbs at 1232 cm⁻¹ in an FTIR spectrum?
A band near 1232 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
Quick answer
A band near 1232 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.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| C-O single bond | 8 | 8 | 1.0 |
| Methacrylate | 7 | 7 | 1.0 |
| Acetate | 7 | 7 | 1.0 |
| Methoxy (OCH3) | 6 | 6 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Secondary amine | 4 | 4 | 1.0 |
| C n single bond | 3 | 3 | 1.0 |
| Phosphorus | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Nitrile | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| C#c | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 0.7 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| polyvinylpyrrolidone | 1232, 1660, 1700 | Methacrylate, Acetate | 1 |
| CA | 1232, 1045, 1650 | Acetate, Methacrylate, C-O single bond | 1 |
| silver nanoparticles (AgNPs) | 1232, 1100, 1749 | Methacrylate, Acetate | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
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 1232 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
Acetate confidence 1.0
“at 3291 -OH and -NH groups, 2922-OH stretching, 1745-carboxyl and carbonyl groups of 2 hemicellulose, 1650amide (-C=O) or N-H bending, 1513-aromatic skeletal vibrations, 1457-OH and -C-O stretching, 1232-C-O stretch, 1159-C-O stretching of”
Adsorption Kinetic and Isotherms of Reactive Red 120 on <i>Moringa oleifera</i> Seed as an Eco-Friendly Process DOI: 10.1016/j.molstruc.2019.05.106 -
Alkene (C=C) confidence 1.0
“The absorbance bands present in the cm-1 nanoparticles at 3283, 2102, 1636, 3264.86, 2104.49 and 1636.62 indicated that alcohol and unsaturated hydrocarbon (O-H stretching vibrations in polyphenols and stretching cm-1 vibrations of the (NH)”
Omomowo 等 - 2020 - Antimicrobial and antioxidant activities of algal- DOI: 10.1088/1757-899X/805/1/012010 -
Amide confidence 1.0
“7.09±0.06 5.59±0.03 cm-1 falls at 1234 for raw wool and 1232 cm-1 for pulled wool, resulting from the Alanine ALA 5.73±0.01 5,88±0.01 combination of C-N and C-C stretching Proline”
Abdellaoui 等 - 2022 - Effect of the Chemical Unhairing Process on Pulled DOI: 10.2478/ftee-2022-0025 -
Acetate confidence 1.0
“aC bend - - 1348 - HC b FC ring stretch - 1296 - 1296 C-O phenolic stretch 1265 - 1257 - C-O phenolic stretch 1232 1209 1228 1211”
Hydrogen Bonding in Human Manganese Superoxide Dismutase Containing 3-Fluorotyrosine DOI: 10.1529/biophysj.105.060616 -
Carbohydrate confidence 1.0
“Assigned to polysaccharides present in gluten.”
Dirin 等 - 2022 - Zein Protein Obtained from Maize as a Novel Biodeg DOI: 10.21203/rs.3.rs-1744529/v1 -
Secondary amine confidence 1.0
“aromatic secondary amine The band observed at cm-1 around 1232 can be assigned to CN stretching vibration species26.”
Fagundes 等 - 2019 - PAni-coated LiFePO4 Synthesized by a Low Temperatu DOI: 10.1590/1980-5373-MR-2018-0566 -
Acetate confidence 1.0
“The main absorption peaks of pure CA were represented by the stretching conductivity, the viscous resistance of the adequate polymer content and the reduced electrostatic vibrations of C=O from ester groups (1743 cm-1), C-O from the carboxy”
Biomimetic Growth of Hydroxyapatite on Electrospun CA/PVP Core–Shell Nanofiber Membranes DOI: 10.3390/polym10091032 -
Amide confidence 1.0
“The two-times amplified difference spectrum indilargestgroups(IR:40.5/17.6%,Raman:28/1.7%),andonlyfew cates numerous positive and negative bands most notable at 1232,1337,1450cm-1 andat1054,1095,1739,2851,2921cm-1, 30 10 spectrawereassigned”
Krafft 等 - 2008 - Raman mapping and FTIR imaging of lung tissue con DOI: 10.1039/b712958k
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