What Makes a Pure Peptide

What does “pure peptide” mean?

A pure peptide is a sample in which the target sequence makes up nearly all of the measured material, reported as an HPLC purity percentage for a specific lot.

The remainder is typically truncated or deletion sequences, residual synthesis reagents, counter-ions and moisture. A purity figure only describes the lot that was tested, which is why it has to be tied to a lot number.

How is peptide purity measured?

High-performance liquid chromatography (HPLC) separates a sample into its components; purity is the target peak's area as a share of all detected peaks.

Some certificates add a mass-spectrometry identity result, which confirms the main peak has the expected molecular mass. Purity says how much of the sample is one component; identity says which component it is.

What purity should a research peptide have?

Research-grade peptides are commonly specified at ≥98% or ≥99% HPLC purity; every DMV Research lot listed below tested at 99.28% or higher.

How does purity differ from net content?

Purity is the share of the sample that is the target peptide; net content is the measured mass of lyophilized powder in the vial against its label claim.

A vial labelled 10 mg can measure above or below 10 mg while still testing at high purity, so a complete certificate reports both figures for the same lot.

How do you check a purity claim?

Match the lot number on the vial to a certificate that names the laboratory, method, analysis date and purity result for that exact lot.