What absorbs at 3295 cm⁻¹ in an FTIR spectrum?
A band near 3295 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 3295 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) | 9 | 9 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Methacrylate | 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 |
| Acetate | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Protein | 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 |
|---|---|---|---|
| polypyrrole | 3295, 1700, 400 | Alkyl C-H, Amide, N h | 1 |
| iron oxide | 3295, 1130, 891 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| TiO | 3295, 1730, 1699 | Alkyl C-H, 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 3295 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 stretching vibrations of poly-OH and C-H, as well as the bending vibrations cm-1, of O-H, were typically attributed to the bands at 3295, 2927, and 1240 cm-1, respectively.”
Formation of Intermediate Amylose Rice Starch–Lipid Complex Assisted by Ultrasonication DOI: 10.3390/foods11162430 -
Alkyl C-H confidence 1.0
“All the spectra examined consist of typical absorption peaks at about 3300 cm-l by (OH stretching), 3295 cm-' ( h C - H stretching), 2950 cm-l (C-H stretching), Downloaded 2255 cm-l (C%C-hC stretching), 2120 cm-l (C%C stretching), 1360-1300”
LANGER 和 MOSS - 1993 - FTIR STUDIES OF TRIMETHYLENE LINKED BIS-DIACETYLEN DOI: 10.1080/10587259308030157 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Molecularly Targeted Photothermal Ablation of Epidermal Growth Factor Receptor-Expressing Cancer Cells with a Polypyrrole–Iron Oxide–Afatinib Nanocomposite DOI: 10.3390/cancers14205043 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Effects of soft X-ray radiation damage on paraffin-embedded rat tissues supported on ultralene: a chemical perspective DOI: 10.1107/S1600577518003235 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
El Mohtadi 等 - 2020 - DIFFERENTIAL ENGULFMENT OF STAPHYLOCOCCUS AUREUS A DOI: 10.17179/excli2020-2766 -
confidence 1.0
“-C=C stretching 2925 C-H stretching 2925 C-H stretching 3295 N-H stretching 3295 N-H stretching”
Effects of Cyclodextrins ( and ) and l-Arginine on Stability and Functional Properties of Mucoadhesive Buccal Films Loaded with Omeprazole for Pediatric Patients DOI: 10.3390/polym10020157 -
confidence 1.0
“cm-1 cm-1 sparfloxacin) there are bands characteristic of sparfloxacin, which definitely confirms its presence: at 3419 and 3295 associated with N-H asymmetric and symmetric stretching vibrations, the The intense bands at 3419 cm-1 and 3295”
Application of FTIR Method for the Assessment of Immobilization of Active Substances in the Matrix of Biomedical Materials DOI: 10.3390/ma12182972 -
Hydroxyl (O-H) confidence 1.0
“However, the two weak O-H bands at 3320 and 3295 cm-1 are, respectively, related to Ti3+ and Fe3+ impurities at the octahedral site [2,29,31].”
In Situ High-Pressure Raman Spectroscopic, Single-Crystal X-ray Diffraction, and FTIR Investigations of Rutile and TiO2II DOI: 10.3390/min13050703
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