What absorbs at 3283 cm⁻¹ in an FTIR spectrum?
A band near 3283 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 3283 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) | 6 | 6 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Hydrogen bond | 2 | 2 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 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 |
|---|---|---|---|
| gelatin | 3283, 1652, 3300 | Amide, Alkyl C-H, N h | 1 |
| sodium alginate | 3283, 1636, 1080 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
| bone | 3283, 1649, 1660 | Amide, Alkyl C-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 3283 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
-
Protein confidence 1.0
“The 3 ʋ̵NH last band of the peak level 3283 represents extending peptide Control Abbreviation Vibrational peak assignments (ANHCOA) bonds in proteins [50] and the stretching vibrations of 3(PO43(cid:3))domain PAO PAOasymmetricstretchinginth”
Application of infrared spectroscopy in the identification of Ewing sarcoma: A preliminary report DOI: 10.1016/j.infrared.2017.05.006 -
Hydroxyl (O-H) confidence 1.0
“The strong, broad peaks occurring at 3283.18 in the leaf spectra cm-1 and at 3318.91 in the stem spectra corresponded to the O-H (stretching) functional Plants2023,12,1702”
Phytochemical Composition of Combretum molle (R. Br. ex G. Don.) Engl. & Diels Leaf and Stem Extracts DOI: 10.3390/plants12081702 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Rotich 等 - 2022 - FT-IR Analysis of Beta vulgaris Peels and Pomace D DOI: 10.1155/2022/2233414 -
confidence 1.0
“The group of unresolved bands at 3332, 3312 (OH), (NH), (NH) and 3283cm-1 3060cm-1 2490cm-1 and corresponds to the bands at ca.”
Rozenberg 等 - 2005 - Low-temperature FTIR spectra and hydrogen bonds in DOI: 10.1016/j.saa.2004.05.024 -
Amide confidence 1.0
“Peaks were observed in the amide A band at 3283 cm-1.”
Self assembly of a Model Amphiphilic Phenylalanine Peptide/ Polyethylene Glycol Block Copolymer in Aqueous Solution DOI: 10.1016/j.bpc.2009.01.008 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
CoronaVac (Sinovac) COVID-19 vaccine-induced molecular changes in healthy human serum by infrared spectroscopy coupled with chemometrics DOI: 10.3906/biy-2105-65 -
Hydroxyl (O-H) confidence 1.0
“stretching vibrations of NH groups in peptide chains and OH stretching of 3283 3283 3283 3282”
Infrared Spectroscopy as a Potential Diagnostic Tool for Medulloblastoma DOI: 10.3390/molecules28052390 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Characterization and Application in Packaging Grease of Gelatin–Sodium Alginate Edible Films Cross-Linked by Pullulan DOI: 10.3390/polym14153199
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