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Peptide content vs purity

Peptide content and purity are two different measurements. Purity is the proportion of the main peak in an HPLC run, while peptide content is the fraction of total mass that is the peptide itself, excluding water, counterions and residual solvents. A 99% pure peptide can still have a net content near 80%, so both values belong on a complete COA.

Related terms

  • Counterion — A counterion is the charged species that pairs with a peptide to form a neutral salt.
  • TFA salt vs acetate salt — TFA salt and acetate salt are the two most common peptide salt forms.
  • Lyophilization — Lyophilization is freeze-drying: water is removed from the frozen peptide solution under vacuum.
  • SPPS — SPPS (solid-phase peptide synthesis) is the standard manufacturing method for therapeutic and cosmetic peptides.

Category: analysis · Part of our peptide glossary · Sourcing question? Ask our engineers — replies within 4 business hours.