What absorbs at 3307 cm⁻¹ in an FTIR spectrum?
A band near 3307 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 3307 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 |
|---|---|---|---|
| N h | 7 | 6 | 1.0 |
| Hydroxyl (O-H) | 6 | 6 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Hydrogen bond | 2 | 2 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Alkene (C=C) | 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 3307 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
-
confidence 1.0
“(cm21) Definition of the spectral assignment Wavenumber 3307 Mainly N-H stretching (amide A) of amide groups of proteins, with the little contribution from O-H stretching”
Jeronimo 等 - 2012 - Detection of Creatine in Rat Muscle by FTIR Spectr DOI: 10.1007/s10439-012-0549-9 -
confidence 1.0
“The peak at 3307 was assigned to cm-1 et al.”
Comprehensive chemical analysis of the flower buds of five Lonicera species by ATR-FTIR, HPLC-DAD, and chemometric methods DOI: 10.1016/j.bjp.2018.06.007 -
Alkene (C=C) confidence 1.0
“The peak at =C-H cm-1 cm-1 3307 In the acidic medium of bath 1, pyrrole loses one electron is due to stretching.”
Thakur 和 Lokhande - 2017 - Effect of dip time on the electrochemical behavior DOI: 10.1515/epoly-2016-0160 -
N h confidence 1.0
“Explicitly assigned in text.”
Spectroscopic and Physicochemical Investigations of Azomethines with Triphenylamine Core towards Optoelectronics DOI: 10.3390/ma15207197 -
confidence 1.0
“Before each aramid structure was confirmed with bands in the regions of cm-1 N-H series of measurements, the validity and repeatability of the 3307 (stretching vibration for in the amide group),”
Bhullar 等 - 2021 - Advanced spectroscopy, microscopy, diffraction and DOI: 10.1039/d0py01348j -
Hydrogen bond confidence 1.0
“In film samples prepared with and without glycerol, cm-1, the O-H stretching band shifted to 3282 indicating strong hydrogen bonding be3307 cm-1 and the signal at about 1630 cm-1 are assigned to O-H stretching vibrations and tween plasticiz”
Bugnotti 等 - 2023 - Structure of Starch-Sepiolite Bio-Nanocomposites DOI: 10.3390/polym15051207 -
Hydroxyl (O-H) confidence 1.0
“ethanol attributed to the C-O group at 1126, 1097, and 1037 are present [42], while the broad ethanol attributed to the C-O group at 1126, 1097, and 1037 cm-1 are present [42], while the broad cm-1 intense band at 3307 is assigned to the st”
Influence of the Heat Treatment on the Particles Size and on the Crystalline Phase of TiO2 Synthesized by the Sol-Gel Method DOI: 10.3390/ma11122364 -
Hydroxyl (O-H) confidence 1.0
“Open PVA, and high viscosity of the PVA solution may play an cm(cid:2)1 O-H tion peaks at 3307 (stretch vibration group) and 1723 important role restraining the free growth and aggregation of cm(cid:2)1”
Fabrication of ascorbyl palmitate loaded poly(caprolactone)/silver nanoparticle embedded poly(vinyl alcohol) hybrid nanofibre mats as active wound dressings via dual-spinneret electrospinning DOI: 10.1039/c7ra03193a
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