What absorbs at 1537 cm⁻¹ in an FTIR spectrum?
A band near 1537 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 1537 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 |
|---|---|---|---|
| Amide | 13 | 13 | 1.0 |
| N h | 7 | 7 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Carbonyl (C=O) | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Ketone | 3 | 3 | 1.0 |
| Ester | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Phosphate (PO4) | 2 | 2 | 1.0 |
| Urethane | 2 | 2 | 1.0 |
| Alkene (C=C) | 2 | 2 | 0.9 |
| Aromatic ring | 1 | 1 | 1.0 |
| Protein beta sheet | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 0 | 1.0 |
| N-O bond | 1 | 0 | 1.0 |
| C c single bond | 1 | 0 | 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 |
|---|---|---|---|
| alginate | 1537, 1100, 1715 | Methacrylate, Amide | 1 |
| collagen | 1537, 1408, 1660 | Amide, Methacrylate, N h | 1 |
| sodium alginate | 1537, 1636, 1080 | Methacrylate, Amide | 1 |
| rGO | 1537, 2358, 2930 | Methacrylate, Amide, N h | 1 |
| hydrogels | 1537, 3281, 1700 | Amide, Methacrylate, N 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 1537 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
-
Urethane confidence 1.0
“tense stretching peak at 1730 cm-1 corresponding to carbonyl groups (C=O), an amide Nthermal, morphological, and physical properties of the EQUIA coat with and without H absorption band at 1537 cm-1 was observed due to the presence of ureth”
Structural, Physical, and Mechanical Analysis of ZnO and TiO2 Nanoparticle-Reinforced Self-Adhesive Coating Restorative Material DOI: 10.3390/ma14247507 -
Urethane confidence 1.0
“LLM confirmed rule peak-group candidate”
A study of molecular architectural dynamics of crosslinked urethane during photo-aging by two-dimensional infrared correlation spectroscopy DOI: 10.1016/j.polymdegradstab.2020.109242 -
confidence 1.0
“cm-1 cm-1 at 1645 for C=O stretch, at 1537 for N-H amide cm-1 bending, and at 1226 for C-O stretch (Fig.”
Owonubi 等 - 2018 - Characterization and in vitro release kinetics of DOI: 10.1007/s40090-018-0139-2 -
Amide confidence 1.0
“cm-1, C-O stretching in The band at 1076 explained 2by symmetrical stretching vibrations of PO phosphodiester groups.19-21 groups, has shown an increase in SARS-CoV-2 cm-1 Bands at 1117 and 1080 may be related to viral RNA stretching).18,21”
Calvo-Gomez 等 - 2022 - Potential of ATR-FTIR-Chemometrics in Covid-19 Di DOI: 10.1021/acsomega.2c01374 -
Amide confidence 1.0
“of hBMECs revealed alterations in the FTIR bands as a function of infection, where infected cells showed alterations in cm-1), cm-1), cm-1), the absorption bands of lipid (2924 amide I protein (1649 amide II protein (1537 cm-1, cm-1, cm-1).”
Elsheikha 等 - 2020 - Impact of Neospora caninum Infection on the Bioene DOI: 10.3390/pathogens9090710 -
Amide confidence 1.0
“In fact, the bands Amide A (3292 cm-1), Amide B (2922 cm-1), Amide I (1626 cm-1), Amide II (1537 cm-1), Proline/Hydroyxproline (1448 cm-1) and Amide III (1236 cm-1), characteristic”
Advantages of External Reflection and Transflection over ATR in the Rapid Material Characterization of Negatives and Films via FTIR Spectroscopy DOI: 10.3390/polym14040808 -
Amide confidence 1.0
“Amide II and amide I vibrations were located at 1537 cm(cid:0) 1, 1537 1530 7 1531 6 1530 7 Amide II and 1628 while vibrations of lipids functional groups were (cid:0)”
Characterization of Covid-19 infected pregnant women sera using laboratory indexes, vibrational spectroscopy, and machine learning classifications DOI: 10.1016/j.talanta.2021.122916 -
Amide confidence 1.0
“For the ALG/dECM composite scaffold membrane, the main cm-1 absorption bands were also observed at around 1632 (amide I, C-O, and C-N stretchcm-1 cm-1 ing), 1537 (amide II), and 1242 (amide III).”
Characteristics and Preparation of Designed Alginate-Based Composite Scaffold Membranes with Decellularized Fibrous Micro-Scaffold Structures from Porcine Skin DOI: 10.3390/polym13203464
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