What absorbs at 3361 cm⁻¹ in an FTIR spectrum?
A band near 3361 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 3361 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) | 5 | 5 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 0.9 |
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 |
|---|---|---|---|
| AgNPs | 3361, 1232, 1048 | N h, Hydroxyl (O-H), Methacrylate | 1 |
| glucose | 3361, 1740, 1400 | Methacrylate, Hydroxyl (O-H), Methoxy (OCH3) | 1 |
| PLA | 3361, 1650, 1073 | Methacrylate, Methoxy (OCH3), 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 3361 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
-
confidence 1.0
“Figure 5 shows the FTIR spectra of the initial and final tomato waste, being able to observe the most intense peak at the 3361 cm-1 wavelength belonging to the N-H bond, OH groups, carboxylic acids and phenolic groups, while the peak at 291”
Green Energy Generated in Single-Chamber Microbial Fuel Cells Using Tomato Waste DOI: 10.3390/su151310461 -
Amine primary confidence 1.0
“fungal strain Penicillium atramentosum KM showed cm-1, three distinct peaks, 3360.72, 1643.82, and 462.86 which are attributed to the stretching vibrations of primary amines, carbonyl stretch vibrations in the amide Fig.”
Extracellular biosynthesis, OVAT/statistical optimization, and characterization of silver nanoparticles (AgNPs) using Leclercia adecarboxylata THHM and its antimicrobial activity DOI: 10.1186/s12934-022-01998-9 -
Hydroxyl (O-H) confidence 1.0
“Furthermore, it can be clearly seen that the relative cm-1 of pure absorbance of the associated hydroxyl-hydroxyl stretching observed initially at 3361”
Miscibility and Hydrogen Bonding in Blends of Poly(4-vinylphenol)/Poly(vinyl methyl ketone) DOI: 10.3390/polym6112752 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Amphiphilic polylactic acidhyperbranched polyglycerol nanoparticles as a controlled release system for poorly watersoluble drugs: physicochemical characterization DOI: 10.1111/j.2042-7158.2011.01260.x -
Hydroxyl (O-H) confidence 1.0
“In the FTIR spectra presented in Figure 4, a strong broad peak approxicm-1 O-H approximately at 3361 cm-1 associated with O-H stretching vibration [41-47] is observed, mately at 3361 associated with stretching vibration [41-47] is observed,”
Synthesis, Purification, and Characterization of Carbon Dots from Non-Activated and Activated Pyrolytic Carbon Black DOI: 10.3390/nano12030298 -
confidence 1.0
“One is due to O-H stretching (3360 the second and third due to N-H symmetric and cm-1 cm-1) asymmetric stretching (3361.23 and 3287.07 and as the hydrogen bonding creates an additional relaxation channel, so the other two will be due to the”
Hema 等 - 2022 - Structural and vibrational study of molecular inte DOI: 10.21203/rs.3.rs-649250/v1 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Electrochemical Determination of Lead & Copper Ions Using Thiolated Calix[4]arene-Modified Screen-PrintedCarbon Electrode DOI: 10.3390/chemosensors9070157 -
Acetate confidence 1.0
“cm1, cm1, cm1 cm1, 1219 A shift in bands was noticed (from 3361 C-O, C-C stretch to 1147 and C-O-C stretch to 3341”
Sibiya 和 Moloto - 2017 - Shape control of silver selenide nanoparticles usi DOI: 10.1515/gps-2016-0057
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