---
title: "Amino acid analysis (AAA) of peptides | Sable Peptides"
description: "Amino acid analysis hydrolyses a peptide and quantifies its residues. How it confirms composition and measures peptide content."
canonical: https://www.sablepeptides.co.uk/ref/amino-acid-analysis
publisher: Sable Peptides Limited (UK company 17488610)
note: Research use only. Not for human or veterinary use.
---

# 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](/ref/net-peptide-content)
-   [How to read a peptide certificate of analysis (COA)](/ref/certificate-of-analysis)
-   [Reference index](/ref)

## Sources

1.  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](https://pubmed.ncbi.nlm.nih.gov/37468754/) · [PMC10444640](https://pmc.ncbi.nlm.nih.gov/articles/PMC10444640/)
2.  Muñoz A et al. Quantification of protein calibrants by amino acid analysis using isotope dilution mass spectrometry. *Anal Biochem*. 2011. PMID: [20807498](https://pubmed.ncbi.nlm.nih.gov/20807498/)
3.  Badgujar D et al. Enantiomeric purity of synthetic therapeutic peptides: A review. *Chirality*. 2024. PMID: [38448043](https://pubmed.ncbi.nlm.nih.gov/38448043/)
4.  PubChem. L-Alanine (C3H7NO2, 89.09 g/mol). CID [5950](https://pubchem.ncbi.nlm.nih.gov/compound/5950)

\---

Research use only. This page describes laboratory chemistry and analytical methods. It is not advice on any use in people or animals.

CoA for every lot — [request yours](/coa-request) and we email it within 2 hours.

Research use only. Not for human or veterinary use.

## Cite this

Research use only. Not for consumption. No health claims.

Plain

Sable Peptides. (2026). amino-acid-analysis. UK Research Peptide Reference. Retrieved 11 October 2026, from https://www.sablepeptides.co.uk/ref/amino-acid-analysis

APA

Sable Peptides. (2026, October 11). \*amino-acid-analysis\*. UK Research Peptide Reference. https://www.sablepeptides.co.uk/ref/amino-acid-analysis

BibTeX

@misc{sable\_amino-acid-analysis\_2026,
  author = {{Sable Peptides}},
  title = {{amino-acid-analysis}},
  year = {2026},
  howpublished = {\\url{https://www.sablepeptides.co.uk/ref/amino-acid-analysis}},
  note = {Accessed 11 October 2026. CC BY 4.0}
}

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Date modified: 2026-10-16

Reviewed by Sable Peptides editorial team · 14 October 2026 · [Editorial policy](/editorial-policy)