What absorbs at 1575 cm⁻¹ in an FTIR spectrum?
A band near 1575 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 1575 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 | 9 | 8 | 1.0 |
| Carboxyl (COOH) | 8 | 7 | 1.0 |
| C c single bond | 5 | 5 | 1.0 |
| N h | 4 | 4 | 1.0 |
| Alkene (C=C) | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Nitrogen heterocycle | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Lewis acid site | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| C=n | 1 | 0 | 0.8 |
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 | 1575, 1660, 2930 | Amide | 1 |
| graphene oxide | 1575, 1150, 3400 | Carboxyl (COOH) | 1 |
| glucose | 1575, 1740, 1400 | Carboxyl (COOH) | 1 |
| TiO2 | 1575, 1700, 1093 | Carboxyl (COOH) | 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 1575 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
-
C c single bond confidence 1.0
“A sharp peak at 1575 corresponds to G-band of pris35-40◦C added to the graphite homogeneous solution in 4 h at graphite due to stretching in the C C bond.”
Fluorometric estimation of amino acids interaction with colloidal suspension of FITC functionalized graphene oxide nanoparticles DOI: 10.1016/j.apsusc.2016.11.070 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Elgamouz 等 - 2019 - The Effects of Storage on Quality and Nutritional DOI: 10.3390/biom9090442 -
Amide confidence 1.0
“The peak around 1575 could be attributed to portantly, peak representing amide I at 1677 cm .”
A case study of poly (aryl ether sulfone) hemodialysis membrane interactions with human blood: Molecular dynamics simulation and experimental analyses DOI: 10.1016/j.cmpb.2020.105742 -
Carboxyl (COOH) confidence 1.0
“Spectra of lactate c r cm-1 ip showed an intense absorbance band at 1575 (Figure 2a);”
Nondestructive assessment of tissue engineered cartilage based on biochemical markers in cell culture media: Application of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy DOI: 10.1039/d1an02351a. -
Amide confidence 1.0
“0.04 cm-1 *1,530 *1,515 The amide II peaks at and result 1575”
Sessa 和 Woods - 2011 - Purity Assessment of Commercial Zein Products Afte DOI: 10.1007/s11746-011-1765-4 -
Acetate confidence 1.0
“The peaks at 1630, 1575 cm-1 was blended with KBr in the ratio of 1:100 for quan1175 have been ascribed to the C O, C C and C O MWCNTs and titative stretching analysis and the weighted mixtures were subjected to mode respectively [11].”
Characterization and some physical studies of PVA/PVP filled with MWCNTs DOI: 10.1016/j.jmrt.2018.04.023 -
confidence 1.0
“The band observed at 1575 was previously ascribed to a vibration 50 of pyridine linked by hydrogen bonds to the catalysts' surface [35].”
TiO2 Catalyzed Dihydroxyacetone (DHA) Conversion in Water: Evidence That This Model Reaction Probes Basicity in Addition to Acidity DOI: 10.3390/molecules27238172 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Influence of the Enzymatic Hydrolysis Using Flavourzyme Enzyme on Functional, Secondary Structure, and Antioxidant Characteristics of Protein Hydrolysates Produced from Bighead Carp (Hypophthalmichthys nobilis) DOI: 10.3390/molecules28020519
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