What absorbs at 1727 cm⁻¹ in an FTIR spectrum?
A band near 1727 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 1727 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 |
|---|---|---|---|
| Carbonyl (C=O) | 24 | 19 | 1.0 |
| Carboxyl (COOH) | 15 | 12 | 1.0 |
| Methacrylate | 13 | 11 | 1.0 |
| Acetate | 13 | 11 | 1.0 |
| Ester | 11 | 9 | 1.0 |
| Amide | 10 | 8 | 1.0 |
| Ketone | 9 | 7 | 1.0 |
| Alkyl C-H | 7 | 7 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Carbohydrate | 5 | 4 | 1.0 |
| N h | 3 | 2 | 1.0 |
| Urethane | 2 | 2 | 1.0 |
| Aldehyde (CHO) | 2 | 2 | 1.0 |
| Acetyl | 2 | 1 | 1.0 |
| Hydroxyl (O-H) | 2 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Protein | 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 |
|---|---|---|---|
| PMMA | 1727, 1722, 1383 | Methacrylate, Acetate, Carbonyl (C=O) | 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 1727 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
-
Acetate confidence 1.0
“Table 3, According to the IR data in W-DHS has characteristic peaks at 1513, 1377, 1194 and cm-1 corresponding to the characteristic peaks of TC-DHS at 1727 (C=O vibration), 1454, 1057 cm-1.”
Discrimination and similarity evaluation of tissue-cultured and wild Dendrobium species using Fourier Transform Infrared Spectroscopy DOI: 10.1016/j.molstruc.2015.01.027 -
Carboxyl (COOH) confidence 1.0
“The GC-MS analysis showed the presence of a single peak, with cm-1 a retention time of 26.5 min, while the disappearance of vibration mode at 1727 was attributed to acid absorption and the FTIR spectrum indicated that formation of an ester”
Djunaidi 等 - 2018 - Synthesis of A Novel Carrier Compound Thiazoethyl DOI: 10.22146/ijc.25075 -
Acetate confidence 1.0
“(i) stretching24 vibration24 842 C-H rocking bond24 4000 3500 3000 2500 2000 1500 1000 500 985 Symmetric stretching C-O (cm-1 Wavelength 1727”
Ionic conductivity and relaxation studies in PVDF-HFP:PMMA-based gel polymer blend electrolyte with LiClO4 salt DOI: 10.1142/S2010135X18500054 -
Carbonyl (C=O) confidence 1.0
“The disappearance of carbonyl peak (at 1727 cm-1) and shifting of hydroxy peak (from 3460 to 3426 cm-1) in the reaction products suggest nucleophilic addition reaction of hydroxy groups with carbonyl”
Goswami 等 - 2004 - One-pot synthesis of a novel water-soluble fullere DOI: 10.1021/cm0350232 -
Carbohydrate confidence 1.0
“The new absorption peak formed near 1727 belongs to hemicellulose [9], which is conducive to the improvement of seed water absorption.”
Luan 等 - 2020 - Spectral characteristics on increasing hydrophilic DOI: 10.1016/j.saa.2020.118350 -
Acetate confidence 1.0
“(c) cm-1, C_O C\O κ-point the stretching at 1727 stretching vibration at atoms, while the D band is a breathing mode of phonons of cm-1 cm-1 sp2 1037 and the remaining character at 1617 [36].”
Nagaraju 等 - 2012 - Na0.33V2O5 center dot 1.5H(2)O nanoringsnanorods DOI: 10.1016/j.ssi.2012.08.014 -
Acetate confidence 1.0
“(†), concerns the bands at 1727 and 1738 These bands ing a linear transition term to the C-O stretch.”
The Raman jet spectrum of trans-formic acid and its deuterated isotopologs: Combining theory and experiment to extend the vibrational database DOI: 10.1063/5.0039237 -
Aldehyde (CHO) confidence 1.0
“In addition, Cya produced a peak at 1727 due to stretching vibration of the cm-1, aldehyde group.”
Improvement of stability due to a cyclamen aldehyde/β-cyclodextrin inclusion complex DOI: 10.1016/j.molstruc.2020.128161
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