Glossary
HPLC purity
Also called HPLC, Purity, Chromatographic purity, High-performance liquid chromatography
The share of the peptide signal in a sample that is the target peptide, measured by high-performance liquid chromatography. It is the percentage most COAs lead with.
In more detail
HPLC pushes a dissolved sample through a packed column. Different molecules travel at different speeds and come out as separate peaks. Purity is the area of the target peak divided by the total peak area, for peptides commonly read with UV light at 214 nm.
What it does not count: water, salts and counterions such as TFA do not show up as peaks in the same way, so a 99% pure powder can still be well under 100% peptide by weight. Purity also says nothing about sterility or endotoxin.
Why it matters
Purity tells you the peptide in the vial is mostly the right peptide. It does not tell you how much of it is there. That is net peptide content or a measured amount per vial.
Related terms
- Certificate of analysis (COA)A document from a testing lab that reports what was measured in a sample: usually identity, purity and sometimes amount and contamination tests.
- Mass spectrometryA test that measures the mass of molecules. On a peptide COA it confirms identity: the measured mass should match the expected mass of the peptide.
- Net peptide contentThe share of a powder's weight that is actually peptide, after water, salts and counterions are excluded. It tells you how much peptide is really in the vial.
- EndotoxinFragments of bacterial cell walls that can cause fever, chills and flu-like reactions when injected. Sterilizing a product does not remove them, so they are tested for separately.
Sources
Each source is labeled by where the information comes from. How we label sources
- Reference workHigh-performance liquid chromatography(opens in a new tab)
Wikipedia · checked
- Vendor guideWhat is peptide purity?(opens in a new tab)
LifeTein · checked
Updated