What is amino acid analysis of peptides? What it can count
Amino acid analysis hydrolyses a peptide and counts the residues. What that proves on a COA, what acid destroys, and how net peptide content is measured.
Tag archive
COA
What are the impurities in synthetic peptides? A COA map
Synthetic peptide impurities by class, from deletion sequences to TFA counterions, and which COA line, HPLC purity or MS mass, can reveal each one.
What Karl Fischer water content means on a peptide COA
Karl Fischer water content on a peptide COA is the water share of the powder by mass. How USP authors subtract it, and what vendor ranges rest on.
How to read a peptide COA: each line, and what it ties to
How to read a peptide COA line by line: what identity, purity, quantity and endotoxin results show, and what a vendor or anonymised COA ties them to.
How to verify a peptide COA is real, and what it leaves open
Four checks the category uses to verify a peptide COA, set against the two conditions 21 CFR 211.84(d)(2) puts on relying on a supplier's analysis.
What MS confirms on a peptide COA that HPLC purity cannot
MS on a peptide COA confirms the observed mass matches the intended molecule. HPLC purity is a peak-area share; it proves neither identity nor mass.
TFA salt vs acetate salt on a peptide COA, assessed
What 'TFA salt' or 'acetate salt' on a peptide COA records, why vials arrive as TFA salts, and how residual TFA is measured, per a 2025 ETH Zurich paper.
Does 99% purity on a peptide COA mean 99% peptide by weight?
No. HPLC purity is a peak-area fraction; net peptide content is a mass fraction. Six sequences show what a TFA counterion alone can take from a 10 mg vial.
Smithers enters peptide testing by buying ACS Laboratory
A testing group founded in 1925 has bought the Florida lab now trading as ACS Peptide Testing Labs. The release is worth reading for what it does not name.
A 70-month sentence puts forged laboratory certificates on the record
The operator of a research-chemical seller was sentenced in late July after admitting the business forged laboratory certificates. For a market that runs on seller-hosted PDFs, that admission is the part worth reading.
The vendor-published certificate of analysis, assessed as evidence
The COA is the central document in research supply and the least examined. Assessed on what it actually establishes, what it leaves open, and how far a buyer can rely on it.
