What absorbs at 3276 cm⁻¹ in an FTIR spectrum?
A band near 3276 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 3276 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) | 8 | 7 | 1.0 |
| N h | 7 | 6 | 1.0 |
| Amide | 6 | 5 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Hydrogen bond | 2 | 2 | 1.0 |
| Secondary amine | 2 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| C n single bond | 1 | 0 | 1.0 |
| Carbonyl (C=O) | 1 | 0 | 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 |
|---|---|---|---|
| PVA | 3276, 1660, 2930 | Alkyl C-H, Hydroxyl (O-H), Amide | 2 |
| Keratin | 3276, 1635, 1717 | Amide, Hydroxyl (O-H), N h | 1 |
| silver nanoparticles | 3276, 1636, 1631 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
| collagen | 3276, 1408, 1660 | Amide, Alkyl C-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 3276 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 spectrum of non-crosslinked PVA cm-1 membrane shows a characteristic peak at 2926 due to asymmetrical stretching of cm-1 C-H bonds, as well as a strong signal at 3276 due to O-H stretching vibrations.”
Highly Conductive Polyelectrolyte Membranes Poly(vinyl alcohol)/Poly(2-acrylamido-2-methyl propane sulfonic acid) (PVA/PAMPS) for Fuel Cell Application DOI: 10.3390/polym13162638 -
Aromatic ring confidence 1.0
“1058 Medium Aromatic C-H in-plane bend 1458 Medium C=C-C aromatic ring stretch Aromatic ring 3276 Strong, broad Hydroxy group, H-bonded OH stretch Alcohol”
The Antimicrobial Activities of Silver Nanoparticles from Aqueous Extract of Grape Seeds against Pathogenic Bacteria and Fungi DOI: 10.3390/molecules26196081 -
Hydroxyl (O-H) confidence 1.0
“2 cm-1 film, O-H Stretching bond PHEA 3276 which contained a lower concentration of PVA, had smaller cm-1 C-H particlescomparedtoF6film,whichhadahigherconcentrationof Aliphatic stretching group 2938”
Influence of Polyvinyl Alcohol (PVA) on PVA-Poly-N-hydroxyethyl-aspartamide (PVA-PHEA) Microcrystalline Solid Dispersion Films DOI: 10.1208/s12249-020-01811-z -
Hydrogen bond confidence 1.0
“The band around 3276 is related mainly to the stretching vibration of the intramolecular hydrogen bond of the amino group of amide A, while 2.3.”
Preparation and Physicochemical Characterization of Softgels Cross-Linked with Cactus Mucilage Extracted from Cladodes of Opuntia Ficus-Indica DOI: 10.3390/molecules24142531 -
Amide confidence 1.0
“The amide A band of dHPI+HSE complexes was slightly shifted to 3276 cm-1, while dHPI+C complex cm-1, band of dHPI+HSE complexes was slightly shifted to 3276 while dHPI+C complex and had no shifts.”
Interactions between Hazelnut (Corylus avellana L.) Protein and Phenolics and In Vitro Gastrointestinal Digestibility DOI: 10.3390/separations9120406 -
confidence 1.0
“the peptide bond oscillate forming spectral bands determined as amideAandamideI-III(Wangetal.,2016).TheamideAbandis 6.5.Thereasonforthisresult maybethat thehydroxyl ion(OH-) metabisulfite (N-H) in the system reacts with sodium to form sodiu”
Du 等 - 2022 - Green and Highly Efficient Wool Keratin Extraction DOI: 10.3389/fmats.2021.789081 -
confidence 1.0
“1238cm-1 for the control and historical samples respectively As shown the collagen in control and historical leather samples 2921cm-1 were associated with N-H in-plane bending and CH wagging is characterized at the wavenumber 3294 and for t”
Investigate the role of fungal communities associated with a historical manuscript from the 17th century in biodegradation DOI: 10.1038/s41529-022-00296-4 -
confidence 1.0
“3, raw IVA r cm-1 cm-1(amide M exhibited characteristic peaks at 3523 (N-H stretching vibration), 3276 a cm-1”
Spray Dried Inhalable Ivacaftor Co-Amorphous Microparticle Formulations with Leucine Achieved Enhanced In Vitro Dissolution and Superior Aerosol Performance DOI: 10.1016/j.ijpharm.2022.121859.
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