What absorbs at 2910 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 2910 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 2910 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

• Alkyl C-H confidence 1.0

  “The peaks at 2910, 1234, and 780 were assigned ν(C-H), δ”

  Wong 等 - 2015 - Synthesis and Characterization of Atomically Flat DOI: 10.1021/jacs.5b03339
• Alkyl C-H confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Synthesis, characterization, and crystallization behaviors of poly(D-lactic acid)-based triblock copolymer DOI: 10.1038/s41598-020-60458-9
• Hydrogen bond confidence 1.0

  “90.9 band includes inter-and intra-molecular hydrogen bond vibrations in cellulose C-H stretching vibration band 2910;”

  Potential effects of nano-cellulose and nano-silica/polyvinyl alcohol nanocomposites in the strengthening of dyed paper manuscripts with madder: an experimental study DOI: 10.1038/s41598-022-23907-1
• Alkyl C-H confidence 1.0

  “cm-1 cm-1 1510 The band at 1400 was due to C-C and C-N stretching, and the peak at 2910 was cm-1 assigned to C-H (e.g., methoxy compounds) stretching vibrations.”

  Removal of Lead(II) from Synthetic Wastewater by Lavandula Pubescens Decne Biosorbent: Insight into Composition–Adsorption Relationship DOI: 10.3390/app10217450
• Alkyl C-H confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Altuntas 等 - 2017 - Biodegradation Properties of Wood-plastic Composit DOI: 10.1002/app.24358
• Hydroxyl (O-H) confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Awais 等 - 2023 - Enhanced Solubility and Stability of Aripiprazole DOI: 10.3390/molecules28093860
• Acetate confidence 1.0

  “Weak bands that appeared in CSAB at 2910 were assigned to vibrations of C=O, respectively.”

  Effective Adsorption of Diesel Oil by Crab-Shell-Derived Biochar Nanomaterials DOI: 10.3390/ma12020236
• Alkyl C-H confidence 1.0

  “On the other hand, the peaks at 2939 cm-1, at 2939 and 2910 referring to the C-H elongation of the alkyl groups, and the peak and 2910 cm-1, referring to the C-H elongation of the alkyl groups, and the peak at 1411”

  Chitosan/PVA Based Membranes Processed by Gamma Radiation as Scaffolding Materials for Skin Regeneration DOI: 10.3390/membranes11080561