What absorbs at 1424 cm⁻¹ in an FTIR spectrum?
A band near 1424 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 1424 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 |
|---|---|---|---|
| Alkyl C-H | 9 | 8 | 1.0 |
| Secondary amine | 5 | 5 | 1.0 |
| Aromatic ring | 4 | 4 | 1.0 |
| C n single bond | 4 | 4 | 1.0 |
| Amide | 4 | 4 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Carbohydrate | 2 | 2 | 1.0 |
| Acetyl | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Bromine | 1 | 1 | 1.0 |
| Protein beta sheet | 1 | 1 | 1.0 |
| Protein alpha helix | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 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 |
|---|---|---|---|
| alginate | 1424, 1100, 1715 | Alkyl C-H | 1 |
| sodium alginate | 1424, 1636, 1080 | Alkyl C-H | 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 1424 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
“The 30 cm-1 peaks in Raman spectra observed at 760.5 and 451.3 relate to the C-H stretching, the peaks 31 32 Accepted cm-1 at 1378.31 and 1054.3 correspond to the C-H bending and the peaks at 1423.8 and 1688.3 2 33 34 cm-1 correspond to the”
Kumar 和 Rao - 2018 - Structural and electrochemical properties of PVP-C DOI: 10.1088/2053-1591/aace40 -
Protein alpha helix confidence 1.0
“in combination with a visible alteration in the protein 1049.1 and 1158.1 to 1161.5 In Muchmore, cm-1 (α-helix β-sheet) region turned to following pathogenic the peaks at 1423.5, 1375.9, and 1052.5 were cm-1”
Synchrotron based phase contrast X-ray imaging combined with FTIR spectroscopy reveals structural and biomolecular differences in spikelets play a significant role in resistance to Fusarium in wheat DOI: 10.1186/s12870-014-0357-5 -
Acetate confidence 1.0
“The strong, broad bond at 1424 region corresponds to vibration that is an asymmetric C-O stretching mode.”
Radulovic 等 - 2017 - The Chemometric Study of Limestone Physico-chemica DOI: 10.2298/SOS1703247R -
Amide confidence 1.0
“https://biointerfaceresearch.com/ 5849 https://doi.org/10.33263/BRIAC125.58455859 cm-1, cm-1, cm-1, 2922 and 2835 C=O stretching at 2094 and 1687 C-N stretching at 1424 and”
Retnoningtyas 等 - 2022 - Synthesis and Characterization of Methionine-Funct DOI: 10.33263/BRIAC125.58455859 -
Carboxyl (COOH) confidence 1.0
“On the other hand, the peaks observed at 1424.16 cm-1 ing of ketones and carboxylic acids, whereas the peak detected at 1621.50 cm-1 revealed and 1325.22 demonstrated O-H bending of carboxylic acids and phenolic compounds.”
Facile Green Synthesis of Zinc Oxide Nanoparticles with Potential Synergistic Activity with Common Antifungal Agents against Multidrug-Resistant Candidal Strains DOI: 10.3390/cryst12060774 -
N h confidence 1.0
“The weak band at 1424 was 4+) δ attributed to asym(NH due to weak Brønsted acidity in agreement with the data obtained for 20.4%TiO 2/SiO 2-G (Figure 5).”
Unravelling water effects on solid acidic catalysts: Case study of TiO 2 /SiO 2 for dehydration of isobutanol DOI: 10.1016/j.jcat.2016.12.007 -
Carboxyl (COOH) confidence 1.0
“value implies (I) ionic and (II) chelating interaction between adsorbate and The peak at 1424 due to carboxylic acid O-H and alcoholic O-H bending of the capsule shifts to 1417 after the sorption of the gold.”
Dangi 等 - 2021 - Polyethyleneimine impregnated alginate capsule as DOI: 10.1038/s41598-021-97228-0 -
Alkyl C-H confidence 1.0
“peaks around 1424 and 1363cm-1 with in situ generated trimetallic (Bi, Fe, and Sn) corresponds to CH deformation modes and the 2 Journal of Chemistry 5 100 80 Transmittance 60 40 20 3500 3000 2500 2000 1500 1000 Wavenumber (cm-1) (a) 100 80”
Dar 等 - 2023 - Study of Antimicrobial Potency of Synthesized Cell DOI: 10.1155/2023/6122583
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.