Amino acid analysis (AAA) of peptides
Amino acid analysis (AAA) of peptides
Last updated: 2026-10-10 · Research use only. Not for human or veterinary use.
Short answer
Amino acid analysis (AAA) breaks a peptide into its amino acids, usually by acid hydrolysis, then quantifies each one chromatographically. It confirms composition ratios and, against an internal standard, gives an absolute peptide amount, which is why it is the reference method for net peptide content. [1]
At a glance
| Term | Definition / specification |
|---|---|
| Hydrolysis | Typical literature conditions: 6 M HCl, ~110 °C, ~24 h [1][2] |
| Separation/detection | Ion-exchange or RP-LC with derivatisation, or LC-MS |
| Outputs | Molar ratios of residues; absolute quantity |
| Residues lost or altered | Trp destroyed; Asn/Gln read as Asp/Glu; Cys and Met partly oxidised |
| Precision aid | Isotope-dilution mass spectrometry |
| Example standard | L-Alanine, PubChem CID 5950 |
Composition check
Measured ratios should match the sequence. A missing or excess residue can flag a deletion or insertion that MS might also detect.
Quantitation
Summing stable residues against a known internal standard gives micromoles of peptide per milligram of powder, from which net content follows.
FAQ
Why is tryptophan not reported?
Standard acid hydrolysis destroys it; alternative hydrolysis conditions are needed.
Can AAA tell D- from L-amino acids?
Not in standard form; chiral methods are required.
Related reference pages
- Net peptide content vs gross weight
- How to read a peptide certificate of analysis (COA)
- Reference index
Sources
- Qasrawi DO et al. Amino acid analysis for peptide quantitation using reversed-phase liquid chromatography combined with multiple reaction monitoring mass spectrometry. Anal Bioanal Chem. 2023. PMID: 37468754 · PMC10444640
- Muñoz A et al. Quantification of protein calibrants by amino acid analysis using isotope dilution mass spectrometry. Anal Biochem. 2011. PMID: 20807498
- Badgujar D et al. Enantiomeric purity of synthetic therapeutic peptides: A review. Chirality. 2024. PMID: 38448043
- PubChem. L-Alanine (C3H7NO2, 89.09 g/mol). CID 5950
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Research use only. This page describes laboratory chemistry and analytical methods. It is not advice on any use in people or animals.
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Research use only. Not for human or veterinary use.