What absorbs at 3278 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 3278 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 3278 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

• Water (H2O) confidence 1.0

  “Water (H 2O) absorbed infrared radiation strongly Figure 6 shows the side view of the Helmholtz coils 3278cm-1.”

  Puspitasari 等 - 2012 - Ammonia Synthesis Using Magnetic Induction Method DOI: 10.1063/1.4757543
• Hydroxyl (O-H) confidence 1.0

  “On the other hand, negative bands at 3278 and O-D could originate from the stretch of Thr76.”

  Suzuki 等 - 2008 - Structural Changes of Salinibacter Sensory Rhodops DOI: 10.1021/bi801358b
• Hydroxyl (O-H) confidence 1.0

  “Other significant difference can also be found 3278 from the O-H stretching.”

  Zou 等 - 2016 - Whole blood and semen identification using mid-inf DOI: 10.1039/C5AY03337C.
• Hydroxyl (O-H) confidence 1.0

  “For pullulan, the broad band in the region around 3278 cm-1 was attributed to the O-H stretching and hydrogen bond originating from water molecules.”

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

  “Sci.2021,11,10230 12of16 days, there was an increase in the transmittance to 3278 cm-1 due to the accumulation of - OH groups in the phenol structures, showing accentuated growth after 7 days.”

  New Insights into the Antioxidant Compounds of Achenes and Sprouted Buckwheat Cultivated in the Republic of Moldova DOI: 10.3390/app112110230
• Amide confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Lipase-catalyzed synthesis and characterization of a novel linear polyamidoamine oligomer DOI: 10.1016/j.polymer.2010.04.071
• Protein confidence 1.0

  “The broad peak at 3278 (i) indicates the H functional groups of the protein and the O-H stretching vibration of the alcohol or pheN-H functional groups of the protein and the O-H stretching vibration of the alcohol or cm-1 nol [50].”

  Study of Antibacterial and Anticancer Properties of bioAgNPs Synthesized Using Streptomyces sp. PBD-311B and the Application of bioAgNP-CNC/Alg as an Antibacterial Hydrogel Film against P. aeruginosa USM-AR2 and MRSA DOI: 10.3390/molecules26216414
• Hydroxyl (O-H) confidence 1.0

  “The characteristic O-H stretching peak at 3278”

  Palayangoda 和 Nguyen - 2012 - AN ATR-FTIR PROCEDURE FOR QUANTITATIVE ANALYSIS OF DOI: 10.3176/oil.2012.4.05