What absorbs at 3327 cm⁻¹ in an FTIR spectrum?
A band near 3327 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 3327 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 |
|---|---|---|---|
| N h | 5 | 4 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Silicon hydride | 1 | 0 | 1.0 |
| Ammonium | 1 | 0 | 1.0 |
| Silicon fluorine | 1 | 0 | 1.0 |
| Silicon (Si) | 1 | 0 | 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 | 3327, 1735, 1650 | Hydroxyl (O-H), Amide | 1 |
| hemicellulose | 3327, 1730, 897 | Hydroxyl (O-H), Amide | 1 |
| GO | 3327, 1720, 1182 | Hydroxyl (O-H), Amide | 1 |
| rGO | 3327, 2358, 2930 | Hydroxyl (O-H), Amide, N h | 1 |
| PCL | 3327, 1751, 1724 | Hydroxyl (O-H), Amide | 1 |
| lignin | 3327, 1035, 1510 | 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 3327 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
“CD3.5 LDPE-vanillin0.9367MD4.4 PlainLDPE0.9296MD4.0 CD3.0 [Fig 1(b)] shows a strong band at 3327, 2924, and cm(cid:1)1 (AOAH) corresponding to phenolic 1746.5 (ACHA), stretching, asymmetric stretching of alkenes (AC¼¼O and stretching of ald”
Blending of low-density polyethylene with vanillin for improved barrier and aroma-releasing properties in food packaging DOI: 10.1002/app.30221 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Maimulyanti 等 - 2019 - Adsorption and recovery of aroma compounds from wa DOI: 10.2306/scienceasia1513-1874.2019.45.446 -
Hydrogen bond confidence 1.0
“The result 3323.20 cm-1 is slightly higher than ASC at the wavenumber of 3327.06 cm-1, indicating that more Nindicates that there are more hydrogen bonds between the peptide chains in ASC than PSC.”
Song 等 - 2019 - Physicochemical and Biocompatibility Properties of DOI: 10.3390/md17030137 -
Amide confidence 1.0
“As shown in Figure 5 and Table S3, the spectrum of FG exhibits characteristic cm-1, cm-1, cm-1, cm-1 cm-1, absorption bands at 1656 1549 1240 3327 and 2958 which absorption bands at 1656 cm-1, 1549 cm-1, 1240 cm-1, 3327 cm-1 and 2958 cm-1,”
Interaction between Negatively Charged Fish Gelatin and Cyclodextrin in Aqueous Solution: Characteristics and Formation Mechanism DOI: 10.3390/gels7040260 -
confidence 1.0
“cm-1 3327 due to the stretching vibrations of the N-H bond, at 2918 and 2849 that corresponded cm-1, to the C-H stretches of -CH and -CH units, and at 1703 which was assigned to the C=O bond 3 2 cm-1 cm-1 of the carboxylic acid moiety in th”
A Mechanism for the Adsorption of 2-(Hexadecanoylamino)Acetic Acid by Smithsonite: Surface Spectroscopy and Microflotation Experiments DOI: 10.3390/min9010015 -
confidence 1.0
“Thus, the broad band centered at 3327 cm-1 was cm´1 N-H stretching vibration of secondary amines, the peak at 1151 corresponds to C-N vibrations, assigned to N-H stretching vibration of secondary amines, the peak at 1151 cm-1 corresponds to”
Magina 等 - 2016 - High Pressure Laminates with Antimicrobial Propert DOI: 10.3390/ma9020100 -
confidence 1.0
“The infrared spectrum representing intense band at a wave number 3327 cm-1 cm-1 showing stretching mode of the N-H bond;”
Instigation of indigenous thermophilic bacterial consortia for enhanced oil recovery from high temperature oil reservoirs DOI: 10.1371/journal. -
Hydroxyl (O-H) confidence 0.9
“Explicit assignment: '3327 cm-1' for L-MeOH, within O-H stretch region.”
Enhancing Thermal and Mechanical Properties of Ramie Fiber via Impregnation by Lignin-Based Polyurethane Resin DOI: 10.3390/ma14226850
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