What absorbs at 1230 cm⁻¹ in an FTIR spectrum?
A band near 1230 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 1230 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 |
|---|---|---|---|
| C-O single bond | 29 | 27 | 1.0 |
| Methoxy (OCH3) | 27 | 26 | 1.0 |
| Methacrylate | 27 | 26 | 1.0 |
| Acetate | 27 | 26 | 1.0 |
| Amide | 11 | 11 | 1.0 |
| Alkyl C-H | 11 | 11 | 1.0 |
| N h | 7 | 7 | 1.0 |
| Phosphate (PO4) | 6 | 6 | 1.0 |
| Aromatic ring | 6 | 5 | 1.0 |
| Secondary amine | 5 | 5 | 1.0 |
| Ester | 5 | 5 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| Nucleic acid | 4 | 4 | 1.0 |
| Carbohydrate | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 3 | 1.0 |
| Silicon-oxygen (Si-O) | 3 | 3 | 1.0 |
| C c single bond | 3 | 3 | 1.0 |
| Alkene (C=C) | 3 | 2 | 1.0 |
| Oxygen heterocycle | 2 | 2 | 1.0 |
| Protein | 2 | 2 | 1.0 |
| Phosphorus | 2 | 2 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| Acetyl | 1 | 1 | 1.0 |
| Sulfur | 1 | 1 | 1.0 |
| S eq o | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 0.9 |
| Sulfonate | 1 | 1 | 0.9 |
| Carbonate | 1 | 1 | 0.9 |
| Phospholipid | 1 | 1 | 0.7 |
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 |
|---|---|---|---|
| Methacrylate | 1230, 873, 1725 | Methacrylate, Acetate, C-O single bond | 1 |
| GO | 1230, 1720, 1182 | Methacrylate, Acetate, C-O single bond | 1 |
| dentin | 1230, 575, 1740 | Methacrylate, Acetate | 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 1230 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
-
Alkyl C-H confidence 1.0
“OH group 1323 CH bending 1250 S=O stretching 1230”
Artemisia 等 - 2019 - The Properties of Brown Marine Algae Sargassum tur DOI: 10.14499/indonesianjpharm30iss1pp43 -
Alkyl C-H confidence 1.0
“Th e band for aromatic ring this band appears in a sample depends on the ratios and concm-1 cm-1 C-H forms a pronounced peak at 1230 in the Lamberton centrations of the contributors.”
Calderon 等 - 2011 - Chemical Differences in Soil Organic Matter Fracti DOI: 10.2136/sssaj2009.0375 -
Acetate confidence 1.0
“FTIRdifferencespectra(initial-finalspectrum).Graphshowspeakshiftsowingtothepolymerisation reaction.Absorbancechangesareseeninthe1160cm-1[v(C-O-C)],1300-1320[v(C-O)]whichshifttolower wavenumbers,at1230and1268cm-1,andabsorbancechangeof[v(C=C)”
Methacrylate peak determination and selection recommendations using ATR-FTIR to investigate polymerisation of dental methacrylate mixtures DOI: 10.1371/journal.pone.0252999 -
Amide confidence 1.0
“Hierarchical clustering of all the spectra of root dentine based cm-1 cm1230 peak corresponds to amide III, and the 1170 cm-1 representing typical dentine on the spectral range of 1700-1200 1 peak corresponds to dehydrated amide III.”
Root canal hydrophobization by dentinal silanization: Improvement of siliconbased endodontic treatment tightness DOI: 10.1002/jbm.b.32874 -
Aromatic ring confidence 1.0
“LLM confirmed rule peak-group candidate”
Identifying the fingerprint of permanganate oxidizable carbon as a measure of labile soil organic carbon using Fourier transform mid‐infrared photoacoustic spectroscopy DOI: 10.1111/ejss.13085 -
Amide confidence 1.0
“silicates amide III, stretch of aromatic rings and carboxylic Shoulder Absent 1230 Combination band SiO2 acids ≅305+964 ≅450+697 or [60], n/a”
FTIR photoacoustic spectroscopy for identification and assessment of soil components_ Chernozems and their size fractions DOI: 10.1016/j.pacs.2020.100162 -
Acetate confidence 1.0
“1230 and the C-O stretching at 1050 The”
Lin 等 - 2015 - Synthesis and characterization of graphene sheets DOI: 10.1007/s10973-015-4968-3 -
Amide confidence 1.0
“Moreover, the amide III vibration at 1230 of droplets surrounded by the viscoelastic layer of polysaccharide in the the conjugates showed a decrease in intensity, suggesting an altered aqueous phase (Xu et al., 2010).The decrease in the ESI”
Effect of different carbohydrates on the functional properties of black rice glutelin (BRG) modified by the maillard reaction DOI: 10.1016/j.jcs.2020.102979
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