What absorbs at 3301 cm⁻¹ in an FTIR spectrum?
A band near 3301 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 3301 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) | 6 | 6 | 1.0 |
| Amide | 5 | 4 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 3 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 1 | 1.0 |
| Ketone | 2 | 1 | 1.0 |
| Ester | 2 | 1 | 1.0 |
| Carbonyl (C=O) | 2 | 1 | 1.0 |
| Acetate | 2 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Amine primary | 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 |
|---|---|---|---|
| collagen | 3301, 1408, 1660 | Amide, N h | 2 |
| alginate | 3301, 1100, 1715 | Hydroxyl (O-H), Carboxyl (COOH), Amide | 1 |
| sodium alginate | 3301, 1636, 1080 | Hydroxyl (O-H), Carboxyl (COOH), Amide | 1 |
| quercetin | 3301, 1745, 1612 | Hydroxyl (O-H), Amide, Carboxyl (COOH) | 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 3301 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
“In FTIR spectra the broad 3301cm-1 asymmetric band centered at can be assigned to the O-H stretching modes of the two hydrogen cm-1 bonds which shows that compound contain water molecules.”
Dalal 等 - 2015 - Structural, electrical, ferroelectric and mechanic DOI: 10.1039/C5RA10501C. -
Amine primary confidence 1.0
“2840-3000 stretching 2978 CeH 1300-1500 bending 1453 OeH 3200-3600 stretching 3301 1600-1650 NH2 bending 1635”
Susceptibility of hybrid sol-gel (TEOS-APTES) doped with caffeine as potent corrosion protective coatings for mild steel in 3.5 wt.% NaCl DOI: 10.1016/j.porgcoat.2019.105478 -
confidence 1.0
“The peak at 3316 cm-1 (observed in mushrooms produced in WS, cm-1 3313 and 3301 for GM and OL, respectively) can be attributed to the N-H stretching vibration and shifted to 3313 and 3301 cm-1 for GM and OL, respectively) can be attributed”
Pleurotus Mushrooms Content in Glucans and Ergosterol Assessed by ATR-FTIR Spectroscopy and Multivariate Analysis DOI: 10.3390/foods9040535 -
Hydroxyl (O-H) confidence 1.0
“For pure PVA, the band at For pure PVA, the band at 3301 cm-1 is attributed to -OH stretching vibration;”
Preparation and Characterization of Polyvinyl Alcohol-Chitosan Composite Films Reinforced with Cellulose Nanofiber DOI: 10.3390/ma9080644 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Dolete 等 - 2019 - Development and sequential analysis of a collagen- DOI: 10.25083/rbl/24.1/108.117 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Characteristics and Preparation of Designed Alginate-Based Composite Scaffold Membranes with Decellularized Fibrous Micro-Scaffold Structures from Porcine Skin DOI: 10.3390/polym13203464 -
Carboxyl (COOH) confidence 1.0
“shielded due to their interaction with cm-1 Additionally, sialic acid presents absorption bands at 3340, 2933 and 1655 (Singh et al., 2020), cm-1 therefore, the peaks at 3301.4 and 2933.4 in CMP spectra (Figure 6) can be attributed to the g”
Iron-caseinglycomacropeptide complexes: characterization and application in beverages DOI: 10.1016/j.foodres.2020.109772 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Refat 等 - 2021 - QuercetinZinc complex and stem cells A new drug DOI: 10.1371/journal.pone.0246265
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