What absorbs at 2369 cm⁻¹ in an FTIR spectrum?
A band near 2369 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 6 cited sources
Quick answer
A band near 2369 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) | 2 | 2 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Carbon dioxide | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| N h | 1 | 1 | 0.8 |
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 |
|---|---|---|---|
| polypyrrole | 2369, 1700, 400 | Alkyl C-H | 1 |
| AgNPs | 2369, 1232, 1048 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| gold nanoparticles | 2369, 1638, 3252 | 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 2369 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 new bands at 2369 and 1519 appeared in FTIR clearly showed structural changes of wool 2θ=33o 47o proteins.”
Gashti 等 - 2015 - Electromagnetic Shielding Response of UV-induced P DOI: 10.1007/s12221-015-0585-9 -
confidence 1.0
“Hence peaks at 2345 in both RHBC and CSBC cm(cid:5)1 50.54(cid:1) -C^Cwhile the peak at are tentatively assigned to and the peak at 2369 in CSBC is due to Ca(OH) (JCPDS card in 2 44.67(cid:1) 78.69(cid:1)”
Biochar production and applications in soil fertility and carbon sequestration – a sustainable solution to crop-residue burning in India DOI: 10.1039/c7ra10353k -
Hydroxyl (O-H) confidence 1.0
“cm-1 The band observed at 2341.58 (curve-1) and 2368.94 cm-1 (curve-2), which are very nearer band, denotes the Evaluation of Ag-Extract NPs by SEM and TEM presence of hydrogen bonded OH stretching of carboxylic The SEM and TEM analyses sho”
Anthelmintic activity of silver-extract nanoparticles synthesized from the combination of silver nanoparticles and M. charantia fruit extract DOI: 10.1186/s12906-016-1219-5 -
Carbon dioxide confidence 1.0
“evolved at 477 and 491 The peak at about 2369 which (cid:2)C was evidenced at 400 indicates the appearance of CO 2.”
Serbezeanu 等 - 2016 - Phosphorus-containing polyimide fibers and their t DOI: 10.1039/c6ra06497c -
Alkyl C-H confidence 1.0
“The cm-1 are associated with C-H stretching and the band at 2369 refers to the CO from 2 band at 896 cm-1 is linked to the axial strains of C-O-C bonds and β-glycosidic bonds cm-1 the atmosphere of the analysis.”
Influence of Silanization Treatment of Sponge Gourd (Luffa cylindrica) Fibers on the Reinforcement of Polyester Composites: A Brief Report DOI: 10.3390/polym14163311 -
N h confidence 0.8
“Explicit assignment: 'An interesting peak observed at 2369 in the NH- spectrum'”
Rajam 等 - 2017 - Monodispersed Gold Nanoparticles as a Probe for th DOI: 10.17344/acsi.2016.3054
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