Protein — FTIR absorption peaks and assignments

Quick answer

Protein 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 Protein

Showing the 30 best-supported peaks of 383 total for Protein.

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

• 1238 cm⁻¹ confidence 1.0

  “The intensity of the cm-1 bands in the 1238-1244 region also decreased in the purified samples, which may be due to the elimination of a small fraction of protein.”

  Ashurov 等 - 2021 - Characterization of polysaccharides from Eremurus DOI: 10.21285/2227-2925-2021-11-2-281-289
• 1637 cm⁻¹ confidence 1.0

  “cm-1 The FTIR band at 1637 corresponds to Amide I of collagen [25] that exists in the raw HAP of bovine bone powder and is completely removed in calcined HAP samples.”

  XRD and FTIR study of A&B type carbonated hydroxyapatite extracted from bovine bone DOI: 10.1063/1.5089399
• 1648 cm⁻¹ confidence 1.0

  “S U cm-1: Region 1700-1000 N cm-1 The vibration 1648 is assigned to C=O stretching of amide I in proteins (mainly - A”

  Fourier transform infrared microspectroscopy detects biochemical changes during C. elegans lifespan DOI: 10.1016/j.vibspec.2019.04.005
• 3283 cm⁻¹ confidence 1.0

  “The 3 ʋ̵NH last band of the peak level 3283 represents extending peptide Control Abbreviation Vibrational peak assignments (ANHCOA) bonds in proteins [50] and the stretching vibrations of 3(PO43(cid:3))domain PAO PAOasymmetricstretchinginth”

  Application of infrared spectroscopy in the identification of Ewing sarcoma: A preliminary report DOI: 10.1016/j.infrared.2017.05.006
• 1645 cm⁻¹ confidence 1.0

  “The peak at 2965 corresponds to asymmetric stretching cm-1 vibrations of CH group in lipids, while band 1645 corresponds to C=O stretching 3 α-helix of proteins.”

  A Preliminary Study of FTIR Spectroscopy as a Potential Non-Invasive Screening Tool for Pediatric Precursor B Lymphoblastic Leukemia DOI: 10.3390/molecules
• 3562 cm⁻¹ confidence 1.0

  “The bands were sharp with broad absorption peaks at 3562 and cm in 29 30 FTIR which showed that the bacterial proteins were responsible for the reduction of sodium 31 selenite to SeNPs.”

  Chandramohan 等 - 2018 - Monodispersed spherical shaped selenium nanopartic DOI: 10.1088/2053-
• 1030 cm⁻¹ confidence 1.0

  “ordered apatite, but a peak at 1030 is indicative of the The collagen in the cornea plays an important role in stoichiometrically ordered apatite [7].”

  Chen 等 - 2006 - Corneal calcification chemical composition of cal DOI: 10.1007/s00417-005-1191-0
• 1678 cm⁻¹ confidence 1.0

  “Strong vibrational coupling signatures observed in our cm-1 In this study, we have applied a selective isotope-labeling stratdata between the carbonyl stretches and the peak at 1678 egy to isolate the vibrational signals of the protein-boun”

  Chenchiliyan 等 - 2023 - Ground-state heterogeneity and vibrational energy DOI: 10.1063/5.0135268