What absorbs at 3371 cm⁻¹ in an FTIR spectrum?
A band near 3371 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 3371 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 |
|---|---|---|---|
| Hydroxyl (O-H) | 9 | 9 | 1.0 |
| N h | 4 | 3 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
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 |
|---|---|---|---|
| sodium alginate | 3371, 1636, 1080 | Hydroxyl (O-H), Alkyl C-H | 1 |
| hemicellulose | 3371, 1730, 897 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| blood | 3371, 2965, 1117 | Hydroxyl (O-H) | 1 |
| curcumin | 3371, 1063, 1153 | Alkyl C-H, Hydroxyl (O-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 3371 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
-
Hydroxyl (O-H) confidence 1.0
“3371cm-1 is due to O-H and N-H groups indicate the presence moisture or the unconverted carbohydrate present in raw biomass.”
Co-pyrolysis of rice straw and water hyacinth_ Characterization of products, yields and biomass interaction effect DOI: 10.1016/j.biombioe.2019.105281 -
Carbohydrate confidence 1.0
“3370.9603cm-1 -OH hemicellulose at conferring to stretch of observation revealed that hemicellulose was of irregular -CH alcohols.”
Zaman 等 - 2021 - Synthesis of Thiol-Modified Hemicellulose, Its Bio DOI: 10.3389/fphar.2021.550020 -
Hydroxyl (O-H) confidence 1.0
“and 3371.31 These bands were attributed to the stretching vibration of O-H and N-H groups in polysaccharides, proteins and fatty acids.”
Characterization and mechanism of lead and zinc biosorption by growing Verticillium insectorum J3 DOI: 10.1371/journal.pone.0203859 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
Fast and Deep Diagnosis Using Blood-Based ATR-FTIR Spectroscopy for Digestive Tract Cancers DOI: 10.3390/biom12121815 -
confidence 1.0
“cm-1 vibration in ethanol shows a peak at 3308.63 with transmittance 75.97 % while N-H stretching cm-1 cm-1 vibration in benzylamine show two peaks at 3371.10 and 3284.83 corresponding to symmetric Page 6/29 and asymmetric (higher frequency”
Hema 等 - 2022 - Structural and vibrational study of molecular inte DOI: 10.21203/rs.3.rs-649250/v1 -
Water (H2O) confidence 1.0
“cm-1 water molecule is shifted to the lower wavenumbers from 3371 for 2 to cm-1 Li+ The stretching vibrations of this water molecule is 3358 for its complex 6 with cation.”
Kurek 和 Barczynski - 2016 - Colchiceine Complexes with Lithium, Sodium and Pot DOI: 10.5562/cca2871 -
Hydroxyl (O-H) confidence 1.0
“Our result cm-1 showed that the O-H stretching vibration of sodium alginate at 3371 was significantly shifted to lower side.”
The Effects of Curcumin Nanoparticles Incorporated into Collagen-Alginate Scaffold on Wound Healing of Skin Tissue in Trauma Patients DOI: 10.3390/polym13244291 -
Water (H2O) confidence 1.0
“OeH and that are assigned to stretching vibrations of SieOHandAleAleOH,apeakat3371cm(cid:3)1correspondstoHeOeH 1627cm(cid:3)1 stretching vibrations of interlayer water, a peak at corHeOeH responds to bending mode of adsorbed water, peaks at”
Curcumin encapsulated dual cross linked sodium alginate/montmorillonite polymeric composite beads for controlled drug delivery DOI: 10.1016/j.jpha.2020.07.002
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.