What absorbs at 3443 cm⁻¹ in an FTIR spectrum?
A band near 3443 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 3443 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) | 20 | 19 | 1.0 |
| N h | 9 | 9 | 1.0 |
| Amide | 6 | 5 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Water (H2O) | 4 | 4 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Ammonium | 1 | 1 | 0.9 |
| Amine primary | 1 | 1 | 0.9 |
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 |
|---|---|---|---|
| Chitosan | 3443, 1650, 1655 | Amide, Hydroxyl (O-H), N h | 1 |
| Polyaniline | 3443, 1565, 1570 | 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 3443 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 peak of 1642 TMPDT shows peaks at 3443 cm-1 indicates the -OH bending vibration of the water molecule while 1089 is the asymmetric strain of the siloxane (Si-O-Si) group.”
Synthesis of N’-(3-trimethoxysilylpropyl)diethylentriamine modified silica (SiO2(RHA)-TMPDT) for adsorption of gold(III) DOI: 10.1063/5.0008267 -
Hydroxyl (O-H) confidence 1.0
“The peak at 3443 is due to presence of hydroxyl group (-OH).”
Mahisagar 等 - 2012 - Deposition of porous low-k thin films using Tween DOI: 10.1117/12.927332 -
Hydroxyl (O-H) confidence 1.0
“The broad band centred at 3443 signifies the stretching collision of H-O-H E bonds that are chemically associated with CdO [23].”
Silver modified cadmium oxide - A novel material for enhanced photodegradation of malachite green DOI: 10.1016/j.ijleo.2018.11.066 -
confidence 1.0
“0.3 Na 2SO solution with pH 11.0, scan rate of 6 Figure4,themainabsorptionpeaksarediscussedhere.The M 4 cm(cid:2)1 peak at 3443 is attributed to the N-H stretching”
Polyaniline with Two Types of Functional Groups: Preparation and Characteristics DOI: 10.1002/macp.200400408 -
Water (H2O) confidence 1.0
“Hydroxyl group from water molecules which is shown by the peak at 3443 disappears by oC.”
Mutrofin 等 - 2018 - Physical-chemistry of Nawangan's phyropyllite and DOI: 10.1088/1757-899X/285/1/012026 -
N-O bond confidence 1.0
“The band at 3428 cm(cid:2)1 cm(cid:2)1 showing very similar behaviour may both be related to M-site vacancies, and the band at 3443 seems to be caused by 3443 cm(cid:2)1 peak no distinct assignment can be proposed.”
Purwin 等 - 2009 - Hydrogen incorporation in Feand Na-doped diopsid DOI: 10.1127/0935-1221/2009/0021-1938 -
Hydrogen bond confidence 1.0
“The FTIR spectrum of pure chitosan 𝑐𝑚-1, shows a broad peak at around 3443.28 which corresponds to the hydrogen bond of -NH and -OH stretching (Barleany et al., 2020).”
Timotius 等 - 2022 - The Study of Methylene Blue Loading into Chitosan- DOI: 10.14716/ijtech.v13i8.6133 -
confidence 1.0
“(Catha edulis) leaf extract can be attributed to hydrogen N-H linked O-H stretching vibrations of phenol, alcohol, carboxbe attributed to C=O bands and the group of proteins 3443cm-1, ylic groups, and other compounds [50, 51].”
Aklilu 和 Aderaw - 2022 - Khat (Catha edulis) Leaf Extract-Based Zinc Oxide DOI: 10.1155/2022/4048120
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