What absorbs at 3287 cm⁻¹ in an FTIR spectrum?
A band near 3287 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 3287 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) | 7 | 7 | 1.0 |
| Amide | 4 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| N c o | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| N h | 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 |
|---|---|---|---|
| PVA | 3287, 1660, 2930 | Hydroxyl (O-H), Acetate, Methacrylate | 1 |
| TiO2 | 3287, 1700, 1093 | Hydroxyl (O-H), Methacrylate, Acetate | 1 |
| collagen | 3287, 1408, 1660 | Amide, Methacrylate, Acetate | 1 |
| TiO2 nanoparticles | 3287, 1700, 455 | Hydroxyl (O-H), Methacrylate, Acetate | 1 |
| Hydroxyapatite | 3287, 1620, 1639 | Hydroxyl (O-H), Methacrylate, Acetate | 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 3287 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
“At 24 h (Figure 6A), there is cm-1, a peak at 3287 corresponding to the presence of OH groups, followed by a peak cm-1,”
Remineralization Potential of Three Restorative Glass Ionomer Cements: An In Vitro Study DOI: 10.3390/jcm12062434 -
Hydroxyl (O-H) confidence 1.0
“Cornstarch PVP CPNCPNCPN0 5 35 O-H stretching 3287”
Jothi 等 - 2021 - Proton conducting polymer electrolyte based on cor DOI: 10.1007/s11581-020-03792-2 -
Hydroxyl (O-H) confidence 1.0
“C-O stretching) and CH (3287.49 -OH stretching, 2917.48 -CH stretching) maintain their place in PVA/CH and PVA/CH/Ag hydrogels.”
Sprayed in-situ synthesis of Polyvinyl alcohol/Chitosan loaded Silver nanocomposite hydrogel for improved antibacterial effects DOI: 10.1016/j.ijbiomac.2019.09.186 -
Hydroxyl (O-H) confidence 1.0
“The presence of the hydroxyl group can be attributed to the peak at 3287 cm-1 attributed to the peak at 3287 and the stretching of the C-O group, ether group, and”
TiO2 Nanoparticle Filler-Based Mixed-Matrix PES/CA Nanofiltration Membranes for Enhanced Desalination DOI: 10.3390/membranes11060433 -
Hydroxyl (O-H) confidence 1.0
“The peak from 3287 cm-1 shows that there was registered valence vibrations ν for the -OH and -NH groups.”
The Comparative Study of the State of Conservation of Two Medieval Documents on Parchment from Different Historical Periods DOI: 10.3390/ma13214766 -
confidence 1.0
“The secondary amino N-H stretching vibration peak near 3287 was weakened and broadened, and shifted towards a lower frequency, which indicated the existence of N-H bond cleavage and the reduction in the degree of hydrogen bonding.”
Che 等 - 2019 - Investigations on Aging Behavior and Mechanism of DOI: 10.3390/ma12213636 -
Amide confidence 1.0
“Amide A band at 3287”
Investigation of proteinaceous paint layers, composed of egg yolk and lead white, exposed to fire-related effects DOI: 10.1038/s41598-020-75876-y -
Hydroxyl (O-H) confidence 1.0
“2359 2360 Absorbed water 2370 2370 Overtone or combination band 3166 3164 (O-H) stretching of water 3435 3435 3433 O-H stretching 3287 3285 [m 3489 3486 Stretching of water (O-H)]”
Effect of preparation conditions on the nanostructure of hydroxyapatite and brushite phases DOI: 10.1007/s13204-015-0509-4
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