What absorbs at 3370 cm⁻¹ in an FTIR spectrum?
A band near 3370 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 3370 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 |
|---|---|---|---|
| Hydroxyl (O-H) | 18 | 18 | 1.0 |
| N h | 9 | 9 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Water (H2O) | 3 | 3 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Phenolic | 1 | 1 | 0.8 |
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 |
|---|---|---|---|
| polyurethanes | 3370, 1740, 1728 | N h, Methacrylate | 1 |
| TiO | 3370, 1730, 1699 | Hydroxyl (O-H), Methacrylate, Methoxy (OCH3) | 1 |
| SiO | 3370, 800, 1745 | Hydroxyl (O-H), Methacrylate, Methoxy (OCH3) | 1 |
| ZnO | 3370, 1400, 3430 | Hydroxyl (O-H), Methacrylate, Methoxy (OCH3) | 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 3370 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
-
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Magnetically Separable Fe3O4/SiO2/TiO2 Photocatalyst Composites Prepared through Hetero Agglomeration for the Photocatalytic Degradation of Paraquat DOI: 10.7454/mss.v25i4.1277 -
confidence 1.0
“either overtone or combination bands at 3370 These CAH peaks could be owing to stretching associated with al- (C„CAH) kyne complexes (Mysen et al., 2009, 2011;”
Stanley 等 - 2014 - Solubility of C-O-H volatiles in graphite-saturate DOI: 10.1016/j.gca.2013.12.013 -
Alkyl C-H confidence 1.0
“Amines, amides, raphy name is used due to the connection of TLC with alcohols, phenols, and alkanes showed main peaks at 3370, the biological activities especially antimicrobial activities.”
Ahmad 等 - 2016 - In Vitro Antimicrobial Bioassays, DPPH Radical Sca DOI: 10.1155/2016/3818945 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Bao 等 - 2021 - Green Extraction of Phenolic Compounds from Lotus DOI: 10.3390/foods10020239 -
Hydroxyl (O-H) confidence 1.0
“As shown in Figure S4 (zoomed part), prominent cm-1 cm-1 O-H 1250 can be attributed to stretching, while bands are because of stretching bands at 1576, 1607, and 1628 cm-1 C-H are due to the stretching of at 2857 and 2924 vibrations of the”
Bir 等 - 2022 - Multifunctional Ternary NLPZnO@L-cysteine-grafted DOI: 10.1021/acsomega.2c04936 -
Ester confidence 1.0
“Increase in the number of spectrum of pristine PUR 20/5, PUR 20/5 + PLA and PUR 20/5 + St showed the presence C=O groups in the PUR 20/5 + PLA blend, resulting from the presence of ester groups in of characteristic bands typical for PUR: st”
Brzeska 等 - 2022 - Susceptibility to Degradation in Soil of Branched DOI: 10.3390/polym14102086 -
Hydroxyl (O-H) confidence 1.0
“The prominent O-H stretch was observed at about 3370 cm-1, due to”
Substantial Proton Ion Conduction in Methylcellulose/Pectin/Ammonium Chloride Based Solid Nanocomposite Polymer Electrolytes: Effect of ZnO Nanofiller DOI: 10.3390/membranes12070706 -
Hydroxyl (O-H) confidence 1.0
“CuCF 0.7 1.1 3.2.3 Morphology of the coated and uncoated fabrics: -OH -NH showed the stretching vibrations of and groups at 3370 6 shows the SEM images of coated and uncoated fabrics.”
Antibacterial activity of hybrid chitosan–cupric oxide nanoparticles on cotton fabric DOI: 10.1049/iet-nbt.2014.0073
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