TFA Salt
Trifluoroacetic acid (TFA) is used as an ion-pairing agent in the mobile phase during reverse-phase HPLC purification. TFA associates with positively charged residues (lysine, arginine, histidine, N-terminus) and co-lyophilizes with the peptide as a counter-ion salt.
TFA salt typically accounts for 10-20% of the gross powder weight, depending on the number of basic residues in the sequence. This is a major contributor to the difference between gross weight and net peptide content.
For research applications where TFA is undesirable (particularly cell culture), peptides can be supplied as acetate or hydrochloride salts instead. Salt exchange is performed through additional purification steps.
All Healthy Aminos products are for research use only.
Related Terms
Net Peptide Content
The percentage of gross powder weight that is actual peptide, accounting for water, counter-ions, and residual solvents.
HPLC
High-Performance Liquid Chromatography — the standard analytical technique for determining peptide purity by separating molecular species based on their chemical properties.
Lyophilization
Freeze-drying — a dehydration process that removes water from a frozen peptide solution under vacuum, producing a stable dry powder.
Research Use Only
FOR RESEARCH USE ONLY. Products sold by Healthy Aminos are intended strictly for in-vitro research and laboratory use. Not for human or animal consumption. Not FDA approved. By purchasing from Healthy Aminos, the buyer acknowledges that these products are not intended to diagnose, treat, cure, or prevent any disease. All products are sold as reference standards and research chemicals only.