Amino acid — FTIR absorption peaks and assignments

Quick answer

Amino acid 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 Amino acid

Showing the 30 best-supported peaks of 152 total for Amino acid.

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

• 1029 cm⁻¹ confidence 1.0

  “Earlier studies have established that the FTIR bands stretching in amino acid has also caused a band at 1029 cm-1 [18,19].”

  Aziz 等 - 2017 - From Insulating PMMA Polymer to Conjugated Double DOI: 10.3390/polym9110626
• 1610 cm⁻¹ confidence 1.0

  “The cm-1 is increasing with increasing temperweak band at 1610 ature and may tentatively be assigned to the amino acid side chain in tyrosine (23).”

  Bertram 等 - 2006 - Heat-induced changes in myofibrillar protein struc DOI: 10.1021/jf0514726
• 1234 cm⁻¹ confidence 1.0

  “stretching mode of groups of serine, threonine, and tyrosine of proteinEE A comparison of the spectra showed significant changes in AmideIII(NAHbending,CANstretch,CACstretch) 1234 Amide III absorbance throughout the whole range tested, i.e.”

  Application of infrared spectroscopy in the identification of Ewing sarcoma: A preliminary report DOI: 10.1016/j.infrared.2017.05.006
• 1607 cm⁻¹ confidence 1.0

  “The bands cm-1) originating from the amino acid side chains vibrations are also observed (1607 [21].”

  A Preliminary Study of FTIR Spectroscopy as a Potential Non-Invasive Screening Tool for Pediatric Precursor B Lymphoblastic Leukemia DOI: 10.3390/molecules
• 3441 cm⁻¹ confidence 1.0

  “Regions of approximately 2352-2938 (-C-C2 cm-1 H-) alkyl absorption peaks and approximately 3441 (-N-H-) amino acid absorption peaks were observed.”

  Chang 等 - 2017 - Material Characteristics of Hair Cuticles after Ha DOI: 10.18494/SAM.2017.1707
• 1731 cm⁻¹ confidence 1.0

  “A band at 1731 represents characteristic of cm-1 α-amino acid hydrochlorides.”

  Crystal Growth, Spectral, Optical, Laser damage, Photoconductivity and Dielectric Properties of Semiorganic L-cystine hydrochloride Single Crystal DOI: 10.1016/j.saa.2015.06.113
• 1400 cm⁻¹ confidence 1.0

  “II band at 1400 indicates the generation of amino acids β-Carotene confirming Bioaccessibility of in In Vitro Digestion.”

  Remodeling of β‑Carotene-Encapsulated Protein-Stabilized Nanoparticles during Gastrointestinal Digestion In Vitro and in Mice DOI: 10.1021/acs.jafc.0c05322
• 2360 cm⁻¹ confidence 1.0

  “The medium doublet bands around 2360 revealed the typical S-H stretching of L-cysteine amino acid, which suggested the possible”

  Mesoporous magnetite nanoparticles synthesis using the Peltophorum pterocarpum pod extract, their antibacterial efficacy against pathogens and ability to remove a pollutant dye DOI: 10.1016/j.molstruc.2018.10.042