What absorbs at 1728 cm⁻¹ in an FTIR spectrum?
A band near 1728 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
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Carbonyl (C=O) | 15 | 13 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 0.95 |
| Amide | 1 | 1 | 1.0 |
| Urethane | 1 | 1 | 0.9 |
| Ester | 1 | 1 | 0.9 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Literature behind these assignments
-
Carbonyl (C=O) confidence 1.0
“Explicit assignment: 'peak at 1728 of C=O'”
Jadhav 和 Jadhav - 2021 - Graft copolymerization of methyl methacrylate onMe DOI: 10.1007/s13726-020-00869-7 -
Amide confidence 1.0
“Explicit assignment.”
Zaman 等 - 2022 - Fabrication of PEGylated Chitosan Nanoparticles Co DOI: 10.3390/molecules27238401 -
confidence 0.95
“Explicit assignment: 'characteristic peak of PHA'”
Vinish 等 - 2015 - Optimizing the nutrient feeding strategy for PHA p DOI: 10.1007/s13762-015-0784-3 -
Carboxyl (COOH) confidence 0.95
“Explicit: 'peak appeared at 1728 cm-1 (Fig. 4b) assigned to the ionized COO- groups'”
da Silva 等 - 2023 - Multifunctional cotton fabrics with novel antibact DOI: 10.1007/s11998-023-00761-y -
confidence 0.9
“Band due to free esters and acids C=O stretch observed at 1728.22 cm-1.”
Firsoni 等 - 2019 - Fiber Content and Relative Feed Value Estimation o DOI: 10.1088/1757-899X/546/4/042008 -
confidence 0.9
“Text: '1728 cm1 (H2O scissoring)'.”
Montano-Miranda 和 Muscat - 2003 - Gas-phase HFvapor etching of thermal silicon diox DOI: 10.4028/www.scientific.net/SSP.92.207 -
Carboxyl (COOH) confidence 0.9
“Text: 'appearance of a COOH peak at 1728'”
Suzuki 等 - 2005 - Fourier transform infrared spectrum of the seconda DOI: 10.1021/bi051237g -
confidence 0.9
“Explicit assignment in text.”
Afolabi 等 - 2021 - Bio-sorption of a bi-solute system of copper and l DOI: 10.1007/s40201-021-00632-x
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