What absorbs at 3003 cm⁻¹ in an FTIR spectrum?
A band near 3003 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 6 cited sources
Quick answer
A band near 3003 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 | 4 | 4 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
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 3003 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 weak peak at 3003 cm-1 was associated with the stretching vibration of CH in the benzene cm-1 The weak peak at 3003 was associated with the stretching vibration of CH in the benzene”
Fabrication of Glass Fiber Reinforced Composites Based on Bio-Oil Phenol Formaldehyde Resin DOI: 10.3390/ma9110886 -
Alkyl C-H confidence 1.0
“Furthermore, cm-1 ν(C-H) the two peaks at about 2951 and 3003 correspond to the vibration modes of methyl groups.”
Nanaki 等 - 2020 - New Biodegradable Poly(l-lactide)-Block-Poly(propy DOI: 10.3390/polym12040852 -
Alkyl C-H confidence 1.0
“Usually, shifted bands between 3003 and 3020 that are due to C-H cis-olefins stretching in denote a high level of unsaturated fatty acids and adulteration with”
Toward the Non-Targeted Detection of Adulterated Virgin Olive Oil with Edible Oils via FTIR Spectroscopy & Chemometrics: Research Methodology Trends, Gaps and Future Perspectives DOI: 10.3390/molecules28010337 -
Alkyl C-H confidence 1.0
“It should be stressed that solvents under study can cm-1 cm-1 C-H vibrations are located at 3003 in the acetone spectrum and at 2984 in the disguise luteolin's peaks so, depending on the solvent, differences can only be seen in cm-1, ethyl”
Solubility of Luteolin and Other Polyphenolic Compounds in Water, Nonpolar, Polar Aprotic and Protic Solvents by Applying FTIR/HPLC DOI: 10.3390/pr9111952 -
confidence 0.8
“Band at approximately 3003 associated to volatile compounds.”
Effect of Frying and Roasting Processes on the Oxidative Stability of Sunflower Seeds (Helianthus annuus) under Normal and Accelerated Storage Conditions DOI: 10.3390/foods10050944 -
confidence 0.6
“Text: 'aromatic protons appeared around 3003'”
Ashraf 等 - 2014 - Preparation and properties of multilayered polymer DOI: 10.1515/polyeng-2013-0297
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