What absorbs at 3288 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 3288 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

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

Possible materials

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 3288 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

  “cm-1 In the chitosan spectra, a broad band at 3288 corresponds to the O-H and N-H cm-1 stretching [37].”

  Aloe Vera extract-based composite nanofibers for wound dressing applications DOI: 10.1016/j.msec.2021.112061
• Hydroxyl (O-H) confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Chemical Composition and Thermogravimetric Behaviors of Glanded and Glandless Cottonseed Kernels DOI: 10.3390/molecules27010316
• confidence 1.0

  “For cm-1, example, around 3288 the stretching vibration of the N-H bonds appears, typically from the protein amino acids.”

  Tenderness of PGI “Ternera de Navarra” Beef Samples Determined by FTIR-MIR Spectroscopy DOI: 10.3390/foods11213426
• Hydroxyl (O-H) confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Screening of Native Trichoderma Species for Nickel and Copper Bioremediation Potential Determined by FTIR and XRF DOI: 10.3390/microorganisms11030815
• Hydroxyl (O-H) confidence 1.0

  “The broad transmission band at roughly 3288 cm-1 can be attributed to the overlapping of hydroxyl group O-H (carboxylic acid), C-O”

  Chemical Treatment of Banana Blossom Peels Adsorbent as New Approach for Manganese Removal: Isotherm and Kinetic Studies DOI: 10.3390/su151310223
• confidence 1.0

  “acterized by a broad medium-intensity absorption band observed in the spectral range 1290 and 1240 cm-1 due to the amide III band, which comprises 30% of C-N stretching, cm-1 cm-1), from 3500 to 3100 (with an absorption maximum at 3288 whic”

  Chemical Profiling and Antimicrobial Properties of Honey Bee (Apis mellifera L.) Venom DOI: 10.3390/molecules26103049
• N h confidence 0.9

  “Explicit assignment in text”

  Nagpal 等 - 2012 - Dissolution enhancement of glimepiride using modif DOI: 10.4103/2230-973X.96925
• N h confidence 0.8

  “Form IV peak at 3288 cm-1”

  Conserved hydrogen bonding in tetrahydrocarbazolone derivatives: influence of solution-state assembly on crystal form nucleation DOI: 10.1039/c4cc10453f