What absorbs at 3160 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 3160 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 authoritative 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 3160 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

  “The peaks at 3463 cm-1 o-phenylenediamine sis of CQDs prepared from showed the and 3160 belong to O-H stretching vibrations whereas a sp2 cm-1 presence of domains predominantly in the carbon core peak at 1612 stems from C=C stretching vibra”

  Structural, optical, and bioimaging characterization of carbon quantum dots solvothermally synthesized from o-phenylenediamine DOI: 10.3762/bjnano.14.17
• confidence 1.0

  “As seen in cm-1, high frequency region, where only a band at around 3160 attributed to N-H stretch, 4a, sample jn-01 shows the vibrational band characteristics of ZIF-8 (ZIF-L) that have been is clearly present for ZIF-L (see Figure 5 and F”

  XRD and Spectroscopic Investigations of ZIF—Microchannel Glass Plates Composites DOI: 10.3390/ma16062410
• N h confidence 1.0

  “The IR spectrum of celecoxib (Figure 2) shows medium cm-1, absorption bands at 3160 and 3260 which were assigned to the drug -NH symmetric and asymmetric intensity and a shift to higher wave numbers.”

  Pandya 等 - 2009 - Formulation, Characterization, and Optimization of DOI: 10.14227/DT160409P22
• Hydroxyl (O-H) confidence 1.0

  “Wide double-peak line in the band cm-1 3160) corresponds to fluctuations of hydroxyl Electrical Conductivity of the Polymer Composites with group.”

  Influence of Ultraviolet/Ozonolysis Treatment of Nanocarbon Filler on the Electrical Resistivity of Epoxy Composites DOI: 10.1186/s11671-016-1577-4
• Hydroxyl (O-H) confidence 1.0

  “der at 3220 with its absorption maximum at 3160 The O-D band covering the”

  Intermolecular Interactions and Spectroscopic Signatures of the Hydrogen-Bonded System—n-Octanol in Experimental and Theoretical Studies DOI: 10.3390/molecules27041225
• Water (H2O) confidence 1.0

  “Hydrogen-bonded water to the gluten network the result of cm-1, 455 hydration by water also form peaks around 3160 contributing to the wide band seen in all 456 samples.”

  Turksoy 等 - 2020 - Effect of aging at different temperatures on LAOS DOI: 10.1016/j.foodhyd.2018.12.055