What absorbs at 3448 cm⁻¹ in an FTIR spectrum?
A band near 3448 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 3448 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) | 30 | 28 | 1.0 |
| N h | 7 | 7 | 1.0 |
| Water (H2O) | 5 | 5 | 1.0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Chitosan | 1 | 1 | 1.0 |
| Carbonate | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 0.9 |
| Carboxyl (COOH) | 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 |
|---|---|---|---|
| chitosan | 3448, 1650, 1655 | Hydroxyl (O-H), N h | 1 |
| chitin | 3448, 1650, 1655 | N 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 3448 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
-
Alkyl C-H confidence 1.0
“The characteristic bands of chitosan including the -OH stretching, C-O stretching, -NH 2 cm-1, bending, and -CH stretching are located at 3448, 1118, 1627, and 2924 while the characteristic 2 cm-1 of fly ash is found at 671 and 493 which sh”
Kusumastuti 等 - 2017 - The Effect of Silane Addition on Chitosan-Fly Ash DOI: 10.1088/1757-899X/172/1/012016 -
Hydroxyl (O-H) confidence 1.0
“Peak at 3448 related to OH group of cellulose acetate.”
Nanostructure and Property of Electrospun SiO2-Cellulose Acetate Nanofiber Composite by Electrospinning DOI: 10.1016/j.egypro.2016.12.133 -
Hydroxyl (O-H) confidence 1.0
“terreus (cm-1) Visible intensity Vibration assignment/functional groups Observed wave number O-H stretch (alcohols and phenols) 3448.32”
Ragavendran 和 Natarajan - 2015 - Insecticidal potency of Aspergillus terreus agains DOI: 10.1007/s11356-015-4961-1 -
Hydroxyl (O-H) confidence 1.0
“The cm-1 cm-1 peaks at 3448.26 and 1636.38 were attributed O-H to the stretching and bending vibrations of groups,”
Effects of BaCl2 on K-feldspar flotation using dodecyl amine chloride under natural pH DOI: 10.1016/S1003-6326(18)64878-2 -
Hydroxyl (O-H) confidence 1.0
“Assigned -OH stretching was observed at 3448 in chitosan cm-1, cm-1 (Table 1).”
Sudatta 等 - 2020 - Extraction, characterization and antimicrobial act DOI: 10.1016/j.ijbiomac.2020.06.291 -
Hydroxyl (O-H) confidence 1.0
“bentonite spectrum exhibit an adsorption bands at 3448 and 1635 These bands were assigned to the stretching and bending respectively of the -OH group from the water molecule that contained in the cm-1 interlayer space of the bentonite.”
Taher 等 - 2018 - Preparation and Characterization of Dabco (1,4-Dia DOI: 10.1088/1757-899X/299/1/012055 -
N h confidence 1.0
“However, B 2g, B 1u, 1u cm(cid:1)1 -NH acrylamide shows stretching at 3448.5 and stretch2 and E are the inactive phonon modes.”
Verma 等 - 2021 - The functionalization of polyacrylamide with MoS2 DOI: 10.1039/d0se01877e -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
Preparation and Composition Optimization of PEO:MC Polymer Blend Films to Enhance Electrical Conductivity DOI: 10.3390/polym11050853
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