What absorbs at 1593 cm⁻¹ in an FTIR spectrum?
A band near 1593 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 1593 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 |
|---|---|---|---|
| Carboxyl (COOH) | 7 | 7 | 1.0 |
| Aromatic ring | 7 | 7 | 1.0 |
| N h | 5 | 5 | 1.0 |
| Carbonyl (C=O) | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| Lignin | 3 | 3 | 1.0 |
| Alkene (C=C) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| C=n | 2 | 2 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Nitro (NO2) | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| Protein beta sheet | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Thiol | 1 | 0 | 0.8 |
| Lewis acid site | 1 | 0 | 0.7 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 1593 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
-
Lignin confidence 1.0
“Additionally, the 1593 peak has been assigned as one of the most characteristic bands for lignin in the fingerprint region (Zhou et al.”
FTIR as an easy and fast analytical approach to follow up microbial growth during fungal pretreatment of poplar wood with Phanerochaete chrysosporium DOI: 10.1016/J.MIMET.2018.01.004 -
Aromatic ring confidence 1.0
“In our study, the phenyl ring further define the thermal limits in rapid high-temperature cm-1 stretching peak at 1593 processing.”
Detecting, characterising and assessing PEEK’s and CF-PEEK’s thermal degradation in rapid high-temperature processing DOI: 10.1016/j.polymdegradstab.2022.110096 -
Water (H2O) confidence 1.0
“- - - C O stretching vibration of carboxylic acid and ester in hemicellulose 1738 Absorbed water 1646 - - - - 1593 1592 1589 Aromatic C C vibration 1594 1592 Lignin component (Rosa et al., 2012) 1505”
Kasyapi 等 - 2013 - Bionanowhiskers from jute Preparation and charact DOI: 10.1016/j.carbpol.2012.10.021 -
Silicon (Si) confidence 1.0
“These cm¡1 distinct peak at 1593 was attributed to a Si-phenyl vibratrimethylsilyl derivatives were studied by IR dispersive speccm¡1 tion.”
Modification of Chrysotile Surface by Organosilanes: An IR–Photoacoustic Spectroscopy Study DOI: 10.1006/jcis.2001.7524 -
Carbohydrate confidence 1.0
“For the cellulose samples treated CI cm(cid:1)1 RA cellulose I, for cellulose II), CI(XD) are divided with CO 2, new bands at 1593 and 1470 are asCII into CI(XD-CI) for cellulose I and CI(XD-CII) for celsigned as hydrogen-bonded carbonyl st”
Oh 等 - 2005 - Crystalline structure analysis of cellulose treate DOI: 10.1016/j.carres.2005.08.007 -
confidence 1.0
“Amine vibration observed at 1593 was shifted to lower wave numbers when the polymer-ceramic nanocomposites were formed.”
Rajakani 和 Vedhi - 2013 - Synthesis and electrochemical studies of TiO2 - Pa DOI: 10.4028/www.scientific.net/AMR.678.263 -
Carboxyl (COOH) confidence 1.0
“LLM confirmed rule peak-group candidate”
Investigation of biosourced carboxymethyl cellulose-ionic liquid polymer electrolytes for potential application in electrochemical devices DOI: 10.1007/s11581-016-1728-8 -
confidence 1.0
“Amine vibration peak observed at 1593 was shifted to lower wave numbers when the polymer-clay nanocomposites were formed.”
Suneetha 和 Vedhi - 2013 - Synthesis, Characterisation and Voltammetric behav DOI: 10.4028/www.scientific.net/AMR.678.258
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