What absorbs at 1327 cm⁻¹ in an FTIR spectrum?
A band near 1327 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 1327 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 |
|---|---|---|---|
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| Methacrylate | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Acetate | 3 | 3 | 1.0 |
| Aromatic ring | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
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 |
|---|---|---|---|
| Sodium alginate | 1327, 1636, 1080 | Methacrylate, C-O single bond, Acetate | 1 |
| silver nanoparticles | 1327, 1636, 1631 | Methacrylate, Acetate, C-O single bond | 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 1327 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
-
Sulfate (SO4) confidence 1.0
“An IR peak at 1327.03 is assigned as anti-inflammatory, (eCeO thyroid, anti-neoplastic, anti-thrombotic antistretch present in a sulfate group [41] and stretching) [42].”
Deepika 等 - 2017 - Photocatalytic degradation of synthetic food dye, DOI: 10.1016/j.jphotobiol.2017.10.015 -
Alkyl C-H confidence 1.0
“structural components of wood because it corresponds to C-H bending of polysaccharides which joins the cm-1 cm-1 band at 1327 of S and G lignin condensed units (Faix 1991).”
Esteves 等 - 2013 - CHEMICAL CHANGES OF HEAT TREATED PINE AND EUCALYPT DOI: 10.4067/S0718-221X2013005000020 -
N-O bond confidence 1.0
“The peak at 1533 is caused by N-O stretching of aromatic nitro cm-1 compounds, the peak at 1386 is caused by symmetric carboxylate stretching, and the peak at 1327 is caused by N-O asymmetric stretching and reveals the presence of a nitro c”
Nematicidal activity of seaweed-synthesized silver nanoparticles and extracts against Meloidogyne incognita on tomato plants DOI: 10.1038/s41598-022-06600-1 -
Acetate confidence 1.0
“The peaks at 1327 and 1262 belong to stretching vibration of C O and C C respectively (Hebeish et al.,”
CMC stabilized nano silver synthesis, characterization and its antibacterial and synergistic effect with broad spectrum antibiotics DOI: 10.1016/j.carbpol.2016.11.083 -
Alkyl C-H confidence 1.0
“TW2 0.08 49.75 6.18 41.66 2.32 xylan C-O vibration in syringyl derivatives and C-H cm-1 1327 vibration in cellulose Aromatic ring vibration combined with CH in”
Aytin 等 - 2022 - Chemical, Hygroscopic, and Mechanical Properties o DOI: 10.15376/biores.17.1.785-801 -
Acetate confidence 1.0
“some of these may be assigned to O-H bending (1408 and 347 cm-1), cm-1), cm-1) 1327 C-O stretching (1243, 1128, 1063 and 1019 C=C bending (965 and 937 and 348 sp2”
Campen 等 - 2022 - Thermal degradation of n-hexadecane base oil and i DOI: 10.1007/s11249-019-1182-7. -
Acetate confidence 1.0
“stretching (C-O-C) polysaccharides Symmetric stretching - 1327 - -”
El-Bana 等 - 2022 - MOLECULAR STRUCTURE AND OPTICAL ATTRIBUTES OF (Na- DOI: 10.4314/bcse.v36i3.19 -
Lignin confidence 1.0
“The pronounced band with a maximum at 1327 cm-1 belongs to the skeletal vibrations of the syringyl ring with the CO stretching vibrations.”
An Efficient Method of Birch Ethanol Lignin Sulfation with a Sulfaic Acid-Urea Mixture DOI: 10.3390/molecules27196356
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