Amino acid analysis (revision 1)
Old revision·09:00, 18 Nov 2024·LedgerLysander
| Amino acid analysis | |
|---|---|
| Abbreviation | AAA |
| Principle | Acid hydrolysis followed by chromatographic quantitation |
| Gives | Residue composition and absolute content |
| Compendial chapter | USP <1052> |
| Analytical method infobox · conventions | |
Amino acid analysis hydrolyses a peptide into its constituent amino acids and quantifies each. It yields two things a chromatographic purity determination cannot: the residue composition, which supports identity, and an absolute peptide content, which supports quantity.[1]
It is one of the few methods that gives content without requiring a reference standard of the peptide itself, because the standards required are the individual amino acids.[2] This makes it particularly valuable for compounds with no marketed product and therefore no compendial standard.[3]
Procedure
[edit]A weighed sample is hydrolysed, conventionally in 6 M hydrochloric acid at 110 °C for 24 hours under vacuum or inert atmosphere. The hydrolysate is derivatised and the amino acids separated and quantified by chromatography against standards of each.[1]
The molar ratios obtained are compared with those expected from the sequence. Agreement supports identity, though it does not establish sequence order — a permutation of the same residues gives the same composition, which is why composition is complementary to mass and fragmentation rather than a substitute for them.