What absorbs at 3253 cm⁻¹ in an FTIR spectrum?
A band near 3253 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 5 cited sources
Quick answer
A band near 3253 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) | 3 | 3 | 1.0 |
| N h | 2 | 1 | 1.0 |
| Ammonium | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 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 |
| Secondary amine | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| PVA | 3253, 1660, 2930 | 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 3253 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
-
Acetate confidence 1.0
“For OI3-oligomer, a broad band at 3253 C-O cm-1 ─NH is primary stretch of amines, a small band near 3017 cm-1 ─C─H appeared due to aromatic stretch.”
Influence of amine‐terminated additives on thermal and mechanical properties of diglycidyl ether of bisphenol A (DGEBA) cured epoxy DOI: 10.1002/app.48404 -
Hydroxyl (O-H) confidence 1.0
“FTIR analysis showed two conspicuous peaks at 3253 and 1461 which correspond to O-H stretch of phenols and N-H bond of primary amines of proteins respectively.”
Cost Effective, Green Synthesis of Copper Oxide Nanoparticles Using Fruit Extract of Syzygium alternifolium (Wt.) Walp., Characterization and Evaluation of Antiviral Activity DOI: 10.1007/s10876-018-1395-1 -
Ammonium confidence 1.0
“The hydroxyl band in CS:Dextran which peaked cm-1 at 3253 showed a shift on the inclusion of various amounts of the ammonium fluoride salt and their intensity lowered significantly.”
Aziz 等 - 2019 - High Proton Conducting Polymer Blend Electrolytes DOI: 10.3390/biom9070267 -
Hydroxyl (O-H) confidence 1.0
“explicit assignment”
Bharudin 等 - 2013 - Condensed Tannins from Acacia Mangium Bark Charac DOI: 10.1063/1.4858646 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Development and In Vitro Evaluation of Biocompatible PLA-Based Trilayer Nanofibrous Membranes for the Delivery of Nanoceria: A Novel Approach for Diabetic Wound Healing DOI: 10.3390/polym13213630
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