Trifluoroacetic Acid (TFA)
Trifluoroacetic Acid (TFA) — A strong organic acid used as an ion-pair reagent in HPLC mobile phases and as the primary cleavage reagent in Fmoc-based peptide synthesis.
What Is Trifluoroacetic Acid?
Trifluoroacetic acid (TFA, CF3COOH) is a strong organic acid (pKa 0.23) used extensively in peptide synthesis and purification. In Fmoc SPPS, TFA (95%) is the standard cleavage reagent that simultaneously removes the peptide from the resin and cleaves all acid-labile side-chain protecting groups. In HPLC, TFA (0.1%) is the standard ion-pairing agent.
Dual Role in Peptide Chemistry
- Cleavage reagent: 95% TFA with scavengers (TIPS, water, EDT) for 2-4 hours cleaves peptides from resin and removes tBu, Trt, Pbf, and Boc groups
- HPLC modifier: 0.1% TFA in mobile phase protonates basic residues, improving peak shape and resolution on reversed-phase columns
- Counter-ion: TFA salts contribute to non-peptide mass in lyophilized products, reducing net peptide content
TFA Removal
TFA counter-ions can be exchanged to acetate or hydrochloride salts by repeated dissolution in dilute acetic acid or HCl followed by lyophilization. This is important for cell-based assays where residual TFA may affect cell viability at high peptide concentrations.
Frequently Asked Questions
What is Trifluoroacetic Acid (TFA)?
A strong organic acid used as an ion-pair reagent in HPLC mobile phases and as the primary cleavage reagent in Fmoc-based peptide synthesis.
Why is Trifluoroacetic Acid (TFA) important in peptide research?
Trifluoroacetic Acid (TFA) is a fundamental concept in reagent as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.
Authority Sources
- Trifluoroacetic Acid (TFA) on Wikipedia
- Search Trifluoroacetic Acid (TFA) on PubChem (NIH)
- Research articles on ScienceDirect