What absorbs at 3284 cm⁻¹ in an FTIR spectrum?
A band near 3284 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 3284 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 | 7 | 7 | 1.0 |
| Hydroxyl (O-H) | 7 | 7 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Protein | 2 | 2 | 0.8 |
| Amine primary | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 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 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 0.8 |
| Amino acid | 1 | 1 | 0.8 |
| Water (H2O) | 1 | 1 | 0.8 |
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 | 3284, 1660, 2930 | Hydroxyl (O-H) | 1 |
| blood | 3284, 2965, 1117 | 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 3284 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
“LLM confirmed rule peak-group candidate”
Functionalization of Rice Husks with Ortho-Phosphoric Acid Enhanced Adsorptive Capacity for Anionic Dye Removal DOI: 10.1007/s42250-020-00142-7 -
Hydroxyl (O-H) confidence 1.0
“Blood (A) can easily be distin- (O-H stretch), 3284.3 (H-bonded O-H stretch), 1646.9 cm)1 (amide I random coil), and 1558.8 (amines bend).”
Elkins - 2011 - Rapid Presumptive Fingerprinting of Body Fluids DOI: 10.1111/j.1556-4029.2011.01870.x -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Improvement of Optical Properties of Functionalized Polyvinyl Alcohol-Zinc Oxide Hybrid Nanocomposites for Wide UV Optoelectronic Applications DOI: 10.1007/s10904-023-02616-w -
Carboxyl (COOH) confidence 1.0
“The ATR-FTIR spectra of Citrus limon leaf extract showed a significant that there is a link between carboxylic acids and alcohols that are intermolecularly bound intensity peak at 3284.2 cm-1 with a wide transmittance band (3700-2800 cm-1).”
Synthesis and Characterization of Sulfur Nanoparticles of Citrus limon Extract Embedded in Nanohydrogel Formulation: In Vitro and In Vivo Studies DOI: 10.3390/gels9040284 -
confidence 1.0
“v(N-H) stretching of amide A Proteins 3284 3282 2959 vas(CH2) and vs(CH2) stretching Lipids, triglycerides, fatty”
Barone 等 - 2020 - Autotrophic and Heterotrophic Growth Conditions Mo DOI: 10.3390/md18030169 -
Hydroxyl (O-H) confidence 1.0
“abundant C-C-H wagging were identified due to the transitions from 1150 to 1500 cm-1 The characteristic -OH stretching was noticed at 3284 due to the presence of 1-”
Multivariate Data Analysis and Central Composite Design-Oriented Optimization of Solid Carriers for Formulation of Curcumin-Loaded Solid SNEDDS: Dissolution and Bioavailability Assessment DOI: 10.3390/pharmaceutics14112395 -
Amine primary confidence 1.0
“Characteristic bands furosemide (spectrum g) are found at 3399.4 and 3350.3 cm-1 (NH2 stretching vibration), 3284.2 cm-1 (Ncm-1 for furosemide (spectrum g) are found at 3399.4 and 3350.3 (NH stretching vibration),”
Garbacz 和 Wesolowski - 2018 - DSC, FTIR and Raman Spectroscopy Coupled with Mult DOI: 10.3390/molecules23092136 -
N h confidence 1.0
“High intensity band assigned to NH.”
Ilic-Stojanovic 等 - 2018 - Thermosensitive hydrogels for modified release of DOI: 10.1080/00914037.2017.1354202
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