Hydroxyl (O-H) — FTIR absorption peaks and assignments

Quick answer

Hydroxyl (O-H) is usually assigned by looking for a recurring cluster of characteristic peaks rather than one exact textbook number. The table below shows where the literature most often places this group in FTIR, ranked by accumulated evidence.

Characteristic FTIR peaks for Hydroxyl (O-H)

Showing the 30 best-supported peaks of 1938 total for Hydroxyl (O-H).

Possible materials

Spectrum logic

A functional-group assignment becomes more confident when several expected bands appear together. Use this page to find the strongest-supported peaks, then confirm that the same sample exhibits a coherent pattern rather than a single isolated hit.

Real-world usage

These pages are useful for unknown material analysis, peak explanation in reports, polymer troubleshooting, and verifying whether a candidate material family is chemically plausible.

Common mistakes

• Using one functional-group page as a complete material verdict without checking the rest of the spectrum.
• Assuming the strongest band is always the most diagnostic one.
• Forgetting that processing, additives, aging, and mixtures can shift or broaden expected peaks.

Verification advice

Use DSC, GC-MS, or TGA when several material families share similar bands or when mixture effects make the FTIR assignment uncertain.

Literature behind these assignments

• 731 cm⁻¹ confidence 1.0

  “Unassociated hydroxyl peaks at 731 and 653 in Raman occurred in the compound”

  Arjunan 等 - 2012 - Quantum chemical studies and vibrational analysis DOI: 10.1016/j.saa.2012.08.053
• 1625 cm⁻¹ confidence 1.0

  “The peak at 1625 in BC was due to OH Quetiapine fumarate at different pH's.”

  Arikibe 等 - 2019 - pH-Responsive Studies of Bacterial CelluloseChito DOI: 10.1002/slct.201902290
• 3429 cm⁻¹ confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Arizka 等 - 2019 - Synthesis and Physical Properties Characterization DOI: 10.1088/1757-899X/546/4/042004
• 2925 cm⁻¹ confidence 1.0

  “The and near 2925cm-1 due to vibration of O-H and Cfucoidan standard has eight peaks the same as the H.”

  Artemisia 等 - 2019 - The Properties of Brown Marine Algae Sargassum tur DOI: 10.14499/indonesianjpharm30iss1pp43
• 3409 cm⁻¹ confidence 1.0

  “The FTIR bands observed at 3409 and 1621 are due to the O-H stretching mode of hydroxyl group.”

  Synthesis and Characterization of Spindle-Like TiO2 Nanostructures and Photocatalytic Activity on Methyl Orange and Methyl Blue Dyes Under Sunlight Radiation DOI: 10.1007/s10876-017-1245-6
• 3426 cm⁻¹ confidence 1.0

  “peak in absorption of 3425.6 which showed the 1033.8 While the variation of PA-2 and PA-5 presence of OH bonds.”

  Aritonang 等 - 2019 - Grafting of Oleic Acid On Cyclic Natural Rubber Re DOI: 10.13005/ojc/350119
• 2925 cm⁻¹ confidence 1.0

  “Two distinctive signals are known as cm-1 functional groups in chitosan molecule including a broad signal at 3415 and a stretching cm-1, cm-1 signal at 2925 which are assigned to existing OH and NH.”

  Mentha piperita essential oils loaded in a chitosan nanogel with inhibitory effect on biofilm formation against S. mutans on the dental surface DOI: 10.1016/j.carbpol.2019.02.018
• 3333 cm⁻¹ confidence 1.0

  “The hydrolytic degradation of PVA nanofibers in the exposure of phosphate buffer solution (PBS) was confirmed by cm21 ATR-FTIR results in which a change at the intensity of the characteristic peak located at 3333 corresponding to hydroxyl g”

  Askari 等 - 2016 - Three-layered electrospun PVAPCLPVA nanofibrous DOI: 10.1002/app.43309