What absorbs at 3223 cm⁻¹ in an FTIR spectrum?
A band near 3223 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 6 cited sources
Quick answer
A band near 3223 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) | 5 | 4 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Amine primary | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Hydrogen bond | 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 | 3223, 1636, 1080 | Hydroxyl (O-H), Alkyl C-H | 2 |
| alginate | 3223, 1100, 1715 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| PLLA | 3223, 1182, 921 | Alkyl C-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 3223 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
-
Hydrogen bond confidence 1.0
“In this experiment the band at 3223 which is usually however this may be related to the precision of the mass balance interpreted as a more highly ordered hydrogen bonding network, used (readability to four decimal places).”
Time series Fourier transform infrared spectroscopy for characterization of water vapor sorption in hydrophilic and hydrophobic polymeric films DOI: 10.1016/j.saa.2020.119371 -
Hydroxyl (O-H) confidence 1.0
“Raft of AR9 formulation showed peaks at 3223.09, 1586.67-1, 1302.64-1, 1162.01-1,and cm-1 1688.17, 1027.74 Disclosure statement due to -OH stretching, ester carbonyl group (C=O) stretchNo potential conflict of interest was reported by the a”
pH responsive alginate polymeric rafts for controlled drug release by using box behnken response surface design DOI: 10.1080/15685551.2016.1231046 -
Hydroxyl (O-H) confidence 1.0
“A strong band at 3223 results from O-H stretching of the cm-1 non-substituted hydroxyl groups of cellulose.”
Ahmed 等 - 2021 - STRUCTURAL AND OPTICAL CHARACTERISTICS OF POLY(VIN DOI: 10.4314/bcse.v35i3.12 -
Alkyl C-H confidence 1.0
“Spectrum of GZ showed prominent -OH cm-1, C-H stretching band at stretching band at 3223.05 cm-1, cm-1 2875.86 and -C=O stretching peak 2947.23 cm-1, C=C stretching vibration at 1656.85 at 1722.43”
Harwansh 和 Deshmukh - 2021 - Formulation and Evaluation of Sodium Alginate and DOI: 10.5530/ijper.55.3.145 -
Amine primary confidence 1.0
“For LDHcm-1 For LDH-SAS, the absorption peaks at about 3411 and 3223 were mainly related to the primary SAS, the absorption peaks at about 3411 and 3223 cm-1 were mainly related to the primary amine cm-1 amine bending vibration of N-H.”
Aging-Resistant Functionalized LDH–SAS/Nitrile-Butadiene Rubber Composites: Preparation and Study of Aging Kinetics/Anti-Aging Mechanism DOI: 10.3390/ma11050836 -
Hydroxyl (O-H) confidence 1.0
“The first strong FTIR - 3223cm-1 OD control OD sample is due to O-H stretching of absorption band at × 100.”
Riyajan 和 Nuim - 2013 - Interaction of Green Polymer Blend of Modified Sod DOI: 10.1155/2013/364253
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