What absorbs at 1570 cm⁻¹ in an FTIR spectrum?
A band near 1570 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 1570 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 |
|---|---|---|---|
| N h | 19 | 18 | 1.0 |
| Carboxyl (COOH) | 15 | 10 | 1.0 |
| Amide | 13 | 11 | 1.0 |
| Secondary amine | 9 | 8 | 1.0 |
| Methacrylate | 8 | 7 | 1.0 |
| Acetate | 8 | 7 | 1.0 |
| Alkene (C=C) | 8 | 6 | 1.0 |
| Carbonyl (C=O) | 7 | 6 | 1.0 |
| Aromatic ring | 6 | 4 | 1.0 |
| Ketone | 5 | 4 | 1.0 |
| Ester | 5 | 4 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| C=n | 4 | 4 | 1.0 |
| C c single bond | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 3 | 1.0 |
| Amine primary | 3 | 3 | 1.0 |
| Protein | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| N-O bond | 2 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| Quinone | 1 | 1 | 1.0 |
| Urethane | 1 | 1 | 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 |
|---|---|---|---|
| cellulose | 1570, 1735, 1650 | Amide | 1 |
| starch | 1570, 1650, 1540 | Amide | 1 |
| HPMC | 1570, 1640, 1550 | Carboxyl (COOH), N h | 1 |
| edible oils | 1570, 1743, 1064 | Carboxyl (COOH) | 1 |
| oil | 1570, 1161, 1163 | Carboxyl (COOH), Amide | 1 |
| graphene | 1570, 1720, 2097 | Amide, 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 1570 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
-
Carbonyl (C=O) confidence 1.0
“The cm-1 above mentioned maximum at the wavenumber of 1570 is also due to an absorption of carbonyl moieties, with the substantial shift towards lower energies resulting that the C=O absorption may be connected with a presence of two carbon”
Mechanical properties, chemical analysis and evaluation of antimicrobial response of Si-DLC coatings fabricated on AISI 316 LVM substrate by a multi-target DC-RF magnetron sputtering method for potential biomedical applications DOI: 10.1016/j.apsusc.2017.03.223 -
Acetate confidence 1.0
“The position of the C=O peak at 1570 cm-1 did not change at different”
Chen 等 - 2020 - Solubility Improvement of Progesterone from Solid DOI: 10.3390/polym12040854 -
C c single bond confidence 1.0
“9, the peak at wave number 1570 between polymer chains, which leads to the decrease in crysC-C C-N (which is responsible for and bending modes of tallinity of M 0.”
Effects of ionic liquid on the hydroxylpropylmethyl cellulose (HPMC) solid polymer electrolyte DOI: 10.1007/s11581-016-1768-0 -
Acetate confidence 1.0
“(OH stretching vibration), 1570 (C=O stretching vibration), 1570 (C=C aromatics), 1180 (C-O vibration) The XRD peaks for palladium has exhibited at 2”
Debataraja 等 - 2018 - Synthesis and Characterization of Nanocomposites o DOI: 10.22146/ijc.26660 -
Carboxyl (COOH) confidence 1.0
“0.0-4.0% methods involve measuring a new peak at 1570 which is 2.5%, 3.0%, 3.5%, and 4.0%) covered the range of FFA 24 C]O interrelated with the group of the carboxylic acid radical content in the samples (expressed as the percentage of ole”
Dong 等 - 2020 - An indirect analytical approach based on ATR-FTIR DOI: 10.1039/d0ra03668d -
Carboxyl (COOH) confidence 1.0
“and subsequently measuring the carboxylate anion band at 1570cm(cid:1)1, was established.”
Determination of the acid values of edible oils via FTIR spectroscopy based on the OH stretching band DOI: 10.1016/j.foodchem.2016.06.035 -
Hydroxyl (O-H) confidence 1.0
“metal-free organic dye combinations (Eosin+N3 and Eosin+N719) rGO shows a broad band at corresponding to the O-H 1570cm-1 stretching mode [46].”
Effect of co-sensitization in solar exfoliated TiO2 functionalized rGO photoanode for dye-sensitized solar cell applications DOI: 10.1016/j.mssp.2019.02.027 -
N h confidence 1.0
“When 5%[AMIM]Cl-PFSA composite membranes was compared conversion rate is 1.5%, decomposition temperature of with PFSA membrane, resulting in a new peak vibration: cm-1 cm-1 triethylamine pretreated and the PFSA film distributed at 3410 is N”
Thermal stability and lifetime of [AMIM]Cl-PFSA composite membranes DOI: 10.1007/s10973-016-6065-7
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