What absorbs at 3378 cm⁻¹ in an FTIR spectrum?
A band near 3378 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 3378 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) | 11 | 11 | 1.0 |
| N h | 3 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Metal hydroxyl | 2 | 2 | 0.9 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Alkyl C-H | 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 |
|---|---|---|---|
| ZnO NPs | 3378, 1664, 875 | Hydroxyl (O-H), N h | 1 |
| ZnO | 3378, 1400, 3430 | Hydroxyl (O-H) | 1 |
| TiO | 3378, 1730, 1699 | Hydroxyl (O-H) | 1 |
| ZnO nanoparticles | 3378, 1219, 1726 | 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 3378 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
“shows characteristic peaks at 3378, 2915, 1560, cm-1 Figure 6 shows FTIR spectra of both leaf powder of 1500, 1380, 1043, 939, 826, 691 and 490 due to OH Becium grandiflorum Becium and ZnO NPs.”
Synthesis and characterization of ZnO nanoparticles using aqueous extract of Becium grandiflorum for antimicrobial activity and adsorption of methylene blue DOI: 10.1007/s13201-021-01373-w -
Hydroxyl (O-H) confidence 1.0
“sativa essential oil has shown strong absorption bands at 3378 and 231 AC cm-1 2848 representing O-H and C-H stretching of polyphenols.”
Antibacterial, antibiofilm and cytotoxic effects of Nigella sativa essential oil coated gold nanoparticles DOI: 10.1016/j.micpath.2015.11.021 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
conferenceseries.iop.org materials science and engineering open access proceedings IOP Conferences Series: Materials Science and Engineering DOI: 10.1088/1757-899X/577/1/012087 -
Hydroxyl (O-H) confidence 1.0
“The peak at 3378 corresponds to the strong broadband of -OH group commonly found in organic molecules attached to cm-1, cm-1, cm-1”
Okpara 等 - 2020 - Green Wastes Mediated Zinc Oxide Nanoparticles Sy DOI: 10.3390/ma13194241 -
Hydroxyl (O-H) confidence 1.0
“A strong peak e cm-1 at 3378 for the stretching vibration of O-H groups was observed in the spectrum of FA, and the cc”
Microencapsulated Soil Conditioner with a Water-Soluble Core: Improving Soil Nutrition of Crop Root DOI: 10.1080/02652048.2020.1836056 -
Acetate confidence 1.0
“Conversely, The infrared spectra of pure Carv and pure TOH (Figure 3A and B, voltammogramsofO.vulgareessentialoil,withCarvasmaincomponent, upperpanels)showtheircharacteristiccontributions.Particularly:v-OH, resemblesthatofpureCarv,withanimp”
Detection of carvacrol in essential oils by electrochemical polymerization DOI: 10.1016/j.heliyon.2020.e03714 -
Hydroxyl (O-H) confidence 1.0
“Figure 3 shows a peak cm-1, around 3378 which corresponds to the strong stretching of the -OH and -NH groups and would be attributed to the presence of water, phenolic compounds, carbohydrates, vitamin C, and polypeptides [58,59], whose pea”
Bioactive Compounds and Sensory Analysis of Freeze-Dried Prickly Pear Fruits from an Inter-Andean Valley in Peru DOI: 10.3390/molecules28093862 -
Hydroxyl (O-H) confidence 1.0
“The FTIR spectrum cm-1, 3378 cm-1, and 3322 of sucrose (Figure 7b) showed O-H stretching vibrations at 3559 cm-1, cm-1, of sucrose (Figure 7b) showed O-H stretching vibrations at 3559 3378 and cm-1, the C-H stretching vibration at 2942 cm-1”
Structural Analysis of Oxidized Sucrose and Its Application as a Crease-Resistant Crosslinking Agent DOI: 10.3390/polym14142842
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