What absorbs at 3221 cm⁻¹ in an FTIR spectrum?
Una banda cerca de 3221 cm⁻¹ puede apuntar a varios grupos funcionales. A continuación se muestran las asignaciones más probables, clasificadas por cuánta evidencia publicada respalda cada una — cada una trazable a literatura (DOI) y validada de forma cruzada con nuestros más de 130,000 espectros de referencia y grafo de conocimiento.
Backed by 3 cited sources
Quick answer
A band near 3221 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.
Posibles asignaciones de grupos funcionales
| Grupo funcional | Hechos de respaldo | Fuentes citadas | Confianza máxima |
|---|---|---|---|
| Carbohydrate | 2 | 2 | 1,0 |
| Hydrogen bond | 2 | 2 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
La clasificación refleja la evidencia acumulada de la literatura, no una única regla autorizada. Siempre confirme según el contexto de su muestra.
Possible materials
| Material | Supporting peaks | Overlapping groups | Fuentes citadas |
|---|---|---|---|
| Cellulose | 3221, 1735, 1650 | Hydroxyl (O-H), Carbohydrate | 2 |
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 3221 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.
Literatura detrás de estas asignaciones
-
confianza 1,0
“cm(cid:0) ◦C 1, 1, 1 SPI/TGA2.0-150 increase in the intensity of this peak with the ad3221 and 2847 There are three auto-peaks at 3440 N-H, O-H, -CH2in Fig.”
Curing mechanism of triglycidylamine crosslinked soybean protein adhesive analyzed by Fourier transform infrared, second derivative infrared and two-dimensional correlation spectroscopy DOI: 10.1016/j.ijadhadh.2021.102825 -
Hydrogen bond confianza 1,0
“hydrogen bonds only in cellulose I The cm-1 is assigned to the intraband at 3221 molecular hydrogen bonds present only in Figure 2: FTIR spectra of buriti, sisal, jute , kenaf , curaua and ramie and vegetal fibers”
Kempaiah 等 - 2020 - FTIR AND WAXS STUDIES ON SIX VEGETAL FIBERS DOI: 10.1016/j.carres.2005.08.007 -
Hydrogen bond confianza 1,0
“The α cm-1 band at 3221 is assigned to the intramolecular hydrogen bonds present only in triclinic I”
Poletto 等 - 2014 - Native Cellulose Structure, Characterization and DOI: 10.3390/ma7096105
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