What absorbs at 3430 cm⁻¹ in an FTIR spectrum?
A band near 3430 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 3430 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) | 55 | 52 | 1.0 |
| N h | 7 | 7 | 1.0 |
| Water (H2O) | 6 | 5 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Methacrylate | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Metal oxygen | 4 | 4 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Alkene (C=C) | 3 | 3 | 1.0 |
| Methoxy (OCH3) | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Ester | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Hydrogen bond | 2 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Oxygen heterocycle | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Phenolic | 1 | 1 | 0.95 |
| Metal hydroxyl | 1 | 1 | 0.9 |
| Silanol (Si-OH) | 1 | 1 | 0.8 |
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 | 3430, 1400, 2353 | Hydroxyl (O-H), Amide | 2 |
| TiO2 | 3430, 1700, 1093 | Hydroxyl (O-H) | 1 |
| polyvinylpyrrolidone | 3430, 1660, 1700 | Amide, Hydroxyl (O-H) | 1 |
| starch | 3430, 1650, 1540 | Hydroxyl (O-H), Amide | 1 |
| polyvinyl alcohol | 3430, 1141, 1640 | Hydroxyl (O-H), Amide | 1 |
| ZnO nanoparticles | 3430, 1219, 1726 | Hydroxyl (O-H), Amide | 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 3430 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
“The FTIR spectra of heat-treated pine and eucalypt wood (Figures 2-5) showed a broadening to lower cm-1 wavenumbers of the band at 3430 corresponding to the O-H stretching vibration from alcohols cm-1) cm-1), (3600-3300 and carboxylic acids”
Esteves 等 - 2013 - CHEMICAL CHANGES OF HEAT TREATED PINE AND EUCALYPT DOI: 10.4067/S0718-221X2013005000020 -
Hydroxyl (O-H) confidence 1.0
“stretching band of surface hydroxyl group”
Low-temperature synthesis of Sr2FeMoO6 double perovskite; structure, morphology, and magnetic properties DOI: 10.1016/j.ceramint.2020.03.264 -
Hydroxyl (O-H) confidence 1.0
“The absorption band at 3430.2 in S04 indicates the presence of OH stretching vibration due to the strong intramolecular hydrogen cm-1 bonding [20].”
Unique Halloysite Nanotubes–Polyvinyl Alcohol– Polyvinylpyrrolidone Composite Complemented with Physico–Chemical Characterization DOI: 10.3390/polym9060207 -
Carbohydrate confidence 1.0
“cm-1 O\\H The broad bands at 3430 were corresponding to the stretching vibrations of amylose or amylopectin (glucose ring), while cm-1 characteristic absorption peaks at 2930 and 1645 were assigned toC\\Hstretchingvibrationandtightlyboundwa”
Gao 等 - 2021 - Synthetic mechanism of octenyl succinic anhydride DOI: 10.1016/j.ijbiomac.2021.01.082 -
Alkyl C-H confidence 1.0
“1390 90.6 89.6 89.3 89.1 78.1 89.3 CH bend 2 C‚O C‚C 1630 86.8 86.7 86.2 86.6 75.1 86.2 or ACAH 2920 87.5 87.2 87.3 86.6 76.9 86.8 stretch OAH 3430 75.5 78.7 77.5 77.8 64.9 75.9 stretch 3740”
Ge 等 - 2017 - Characteristics of activated carbon remove sulfur DOI: 10.1016/j.sjbs.2016.12.016 -
Metal oxygen confidence 1.0
“There are three intense and important peaks in the ZnO spectrum at 3430cm-1, Zn-O, C-O, 580, 1440, and which are originated from and -OH stretching vibrations, respectively.”
Gharagozlou 和 Naghibi - 2018 - Sensitization of ZnO nanoparticles by metal-free p DOI: 10.1016/j.jlumin.2017.12.020 -
Acetate confidence 1.0
“8 cm-1 from The ZnO FTIR spectrum shows three major peaks at 3430, 1440, and 580 the hydroxyl group, C-O, and Zn-O vibrations, respectively.”
Sensitization of ZnO nanoparticle by vitamin B12: Investigation of microstructure, FTIR and optical properties DOI: 10.1016/j.materresbull.2016.07.029 -
Hydroxyl (O-H) confidence 1.0
“The FTIR spectrum of the 1643cm(cid:2)1 TiO(OH) showed characteristic bands at 3430 and 2”
Biological approach to synthesize TiO2 nanoparticles using Aeromonas hydrophila and its antibacterial activity DOI: 10.1016/j.saa.2012.12.083
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