What absorbs at 3397 cm⁻¹ in an FTIR spectrum?
A band near 3397 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 3397 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) | 13 | 13 | 1.0 |
| Water (H2O) | 3 | 3 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| Ammonium | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
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 |
|---|---|---|---|
| polysaccharide | 3397, 1637, 1320 | Hydroxyl (O-H), N h | 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 3397 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
“The AAP-NPs and AAP shared a broad band in the cm-1, and both had a strong characteristic absorption peak at 3397 which was caused by the 3000-3750 cm-1 region, and both had a strong characteristic absorption peak at 3397 cm-1, O-H stretchi”
Formation Optimization, Characterization and Antioxidant Activity of Auricularia auricula-judae Polysaccharide Nanoparticles Obtained via Antisolvent Precipitation DOI: 10.3390/molecules27207037 -
Hydroxyl (O-H) confidence 1.0
“Characteristic data for NS particm(cid:2)1 cles are absorption peaks at 3397 and 1106 t=B A 100 ð1Þ DC% 1 ð Þ (cid:3) ¼ (cid:2) t0 related to hydroxyl and Si-O-Si groups, respectively.”
Ghaemy 和 Bekhradnia - 2012 - Thermal and photocuring of an acrylate-based coati DOI: 10.1007/s11998-012-9401-2 -
Hydroxyl (O-H) confidence 1.0
“Disappearance of carbonyl peak and theappearance of sharp cm21 And secondly, the two hydroxy groups of different fullerene hydroxy peak at 3396.6 in the product also suggested cores may react with two carbonyl groups of the same epoxy that”
Goswami 等 - 2003 - A selective reaction of polyhydroxy fullerene with DOI: 10.1016/S0032-3861(03)00241-6 -
Hydroxyl (O-H) confidence 1.0
“These peaks are similar observed with cm-1 the FTIR result of GO with absorption peaks at 3397, 1730 and 1624 are assigned to (OH), (C=O), (C=C), respectively, that has been reported by Liu et al.”
Synthesis, Characterization, and Performance of Graphene Oxide and Phosphorylated Graphene Oxide as Additive in Water-Based Drilling Fluids DOI: 10.1016/j.apsusc.2019.145005 -
Hydroxyl (O-H) confidence 1.0
“the time and added enzyme effects were evaluated, cm-1) which resulted in the conversion of 50 and 45% of the unsaturation peak (3009 for the 24 h reactions with and without acrylic immobilization, respectively, in addition to cm-1), altera”
Montenegro 等 - 2023 - Enzymatic and Synthetic Routes of Castor Oil Epoxi DOI: 10.3390/polym15112477 -
Ammonium confidence 1.0
“3397 The first two peaks can be assigned to s(NH 3) (cid:238)”
Pena 等 - 2004 - Identification of surface species on titania-suppo DOI: 10.1021/jp0313122 -
Hydroxyl (O-H) confidence 1.0
“The typical peak at 3397 with stretching mode of vibration seen in the unpurified spectrum is attributed to the presence of alcohol (O-H) group.”
Chemometric analysis of cow dung ash as an adsorbent for purifying biodiesel from waste cooking oil DOI: 10.1038/s41598-017-09881-z -
Lipid confidence 1.0
“cm-1, ThePC2loadingplotshowsremarkablepositivevaluespeakingat3736, 3461, 3397 cm-1, 3022sh, 2962, 2926, 2878sh, and 2857 characteristic of lipids.”
The Role of the Preanalytical Step for Human Saliva Analysis via Vibrational Spectroscopy DOI: 10.3390/metabo13030393
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.