What absorbs at 3342 cm⁻¹ in an FTIR spectrum?
A band near 3342 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 3342 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) | 10 | 10 | 1.0 |
| N h | 5 | 3 | 1.0 |
| Alkyl C-H | 4 | 3 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Amide | 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 |
|---|---|---|---|
| cellulose | 3342, 1735, 1650 | Alkyl C-H, Hydroxyl (O-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 3342 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
“These spectra (700-4000 cm-1 simply show the spectra of wood: the 3342 peak shows strong main OH stretching, cm-1 and 2800-3000 shows C-H stretching in methyl and methylene groups.”
n-Heptadecane-Impregnated Wood as a Potential Material for Energy-Saving Buildings DOI: 10.3390/f13122137 -
Hydroxyl (O-H) confidence 1.0
“Strong primary OH stretching can be seen in peaks measuring cm-1, 3342 while C-H stretching in methyl and methylene groups can be seen in peaks”
Can 等 - 2023 - Choline Chloride-Based Deep Eutectic Solvent-Treat DOI: 10.3390/f14030569 -
Hydroxyl (O-H) confidence 1.0
“Page 1/1 ethanolic leaf extract shows characteristic band that as the concentration of the extracts was cm-1 at 3342 corresponds stretching vibration of increased, DPPH radical scavenging activity also -OH and-H bonded alcoholic and phenoli”
Shobitharai 等 - 2021 - Microwave Assisted Extraction of Papaya Leaves and DOI: 10.9734/JPRI/2021/v33i51A33475 -
Alkyl C-H confidence 1.0
“cm-1,C-H ThespectraofrawpastesofAdsealdetectedthebandsofOHstretchingat3342 cm-1 cm-1 ≈1340 at 2980-2800 and [21,33,34], carbonyl group (C=O) at 1670 and 1602 [23], cm-1 cm-1, ≈ C=C of the benzene ring at 1518 [35], CH group 1450 phosphate o”
Abu Zeid 和 Edrees - 2022 - Hydration Characterization of Two Generations of M DOI: 10.3390/app12073517 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Effect of pH on the Reduction of Graphene Oxide on its Structure and Oxygen Reduction Capabilities in the Alkaline Media DOI: 10.1002/elan.201800177 -
Hydroxyl (O-H) confidence 1.0
“At 0 °C, the position of the νOH peak was located at 3342 cm-1 when the sugar was dried from pure water.”
Stabilization of Dry Sucrose Glasses by Four LEA_4 Proteins from Arabidopsis thaliana DOI: 10.3390/biom11050615 -
N h confidence 1.0
“For example, the amide νNH band of valsartan and sacubitril exhibit For example, the amide band of valsartan and sacubitril exhibit peaks in the 3342~3500 S-valsartan and sacubitril.”
Study on Co-Crystallization of LCZ696 Using In Situ ATR-FTIR and Imaging DOI: 10.3390/cryst10100922 -
Hydroxyl (O-H) confidence 1.0
“(2013) also showed that the peak that appeared at 3342 was cm-1 due to the OH stretching of alpha-cellulose.”
Chemical functional groups of extractives, cellulose and lignin extracted from native Leucaena leucocephala bark DOI: 10.1007/s00226-020-01258-2
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