Glossary · 2026-09-24
Scientific lead: Alice Kay, Ph.D.
TFA salt on a peptide lot report
Trifluoroacetate, often shortened to TFA, is a counter-ion that can remain after a synthetic peptide is cleaved and purified. The salt is part of the weighed solid. It changes both the mass of the species and the share of that solid that is peptide. A Certificate of Analysis may say "TFA salt," "trifluoroacetate," or it may be silent. Silence is not permission to fill the blank.
This catalogue does not publish a house equation that converts a TFA salt weight into free-peptide weight. Receivers copy the phrase printed on the PDF. The same point is in how to read a peptide Certificate of Analysis and in how peptide purity is measured. Chromatographic purity and salt form answer different questions. Research use only.
Published lot files for this catalogue are indexed in the certificates library. This definition does not add a report, and it does not assign a task identifier. Research use only.
Frequently asked questions
- Does every lyophilized vial on this site contain a TFA salt?
- No. Copy the species named on the lot file you opened. If the file does not name a salt, leave the salt line blank in the study file.
- Can an HPLC area percent replace a TFA conversion?
- No. An area percent describes separation under a stated method. It does not convert gross weight into free peptide.
Research use only. BlueNex Labs does not provide medical or veterinary advice. Confirm your institution’s policies before purchase. How a comparison or class note is checked sits on documentation standards. The biochemist of record is Alice Kay, Ph.D.