What absorbs at 1328 cm⁻¹ in an FTIR spectrum?
A band near 1328 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 1328 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 |
|---|---|---|---|
| Alkyl C-H | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Chlorine | 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 |
|---|---|---|---|
| PVA | 1328, 1660, 2930 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 2 |
| soil | 1328, 575, 1240 | Alkyl C-H, Carboxyl (COOH), Methacrylate | 1 |
| TiO2 | 1328, 1700, 1093 | Alkyl C-H, Methacrylate, Carboxyl (COOH) | 1 |
| chitosan | 1328, 1650, 1655 | Alkyl C-H, Methacrylate, Methoxy (OCH3) | 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 1328 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
-
Chlorine confidence 1.0
“-1 corresponding to vibration bands of CS-nZVI in the range of 40 0 - 40 0 0 cm .The broad and intense -1 -1 -H peak around 3394 cm correspond to the presence of O stretching from alcohol, 1632 cm is -1 -O -H attributed to H bending, the pe”
Bottom-up approach synthesis of core-shell nanoscale zerovalent iron (CS-nZVI): Physicochemical and spectroscopic characterization with Cu(II) ions adsorption application DOI: 10.1016/j.mex.2020.100976 -
Amide confidence 1.0
“and the shift of amide III peak (1328.2 to cm-1 cm-1) which peaks (1423.5 and 1052.5 1331.6 are shifted in both Sumai3 and Muchmore.”
Synchrotron based phase contrast X-ray imaging combined with FTIR spectroscopy reveals structural and biomolecular differences in spikelets play a significant role in resistance to Fusarium in wheat DOI: 10.1186/s12870-014-0357-5 -
Alkyl C-H confidence 1.0
“The characteristic band appearing cm-1 1328cm-1 at 1410 is assigned to C-H bend of CH of PVA which is shifted to in the composite.”
Sathish 等 - 2013 - Nano Composite PVA-TiO2 Thin Films for OTFTs DOI: 10.4028/www.scientific.net/AMR.678.335 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Chitosan/PVA Based Membranes Processed by Gamma Radiation as Scaffolding Materials for Skin Regeneration DOI: 10.3390/membranes11080561 -
Acetate confidence 1.0
“cm-1 In our research, we also recorded a decrease in absorbances at bands 1421 (aromatic ring cm-1 C-H vibration in lignin combined with deformation in carbohydrates) and 1328 (C-O vibration in syringyl plus guaiacyl derivatives is characte”
Effect of Sunlight on the Change in Color of Unsteamed and Steamed Beech Wood with Water Steam DOI: 10.3390/polym14091697 -
Acetate confidence 1.0
“The band at cm-1 1328 could be related to C-O stretching of acid groups [27] or to bending vibrations of -CH or -CH 3 2 cm-1”
Oliveira 等 - 2016 - FTIR analysis and quantification of phenols and fl DOI: 10.1590/S1517-707620160003.0072 -
Aromatic ring confidence 1.0
“the binary Z?MA IS with quinoid groups [33-35], while the bands at 1520 253 cm-1 201 diffusion coefficient of the electrolyte (MA), / is the elecand 576 are associated with aromatic rings [34], 254 e cm-1 202 trode pathlength, n is the refr”
Salavagione 等 - 2005 - Study of redox mechanism of poly(o-aminophenol) us DOI: 10.1016/j.jelechem.2004.10.013 -
Carbohydrate confidence 1.0
“The vibration band at cm-1 cm-1 1328 shows the presence of pectin (-COOH).”
Shafiquzzaman 等 - 2022 - Sawdust Recycling in the Development of Permeable DOI: 10.3390/su141811115
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