Glossary
Mass spectrometry
Also called Mass spec, MS, LC-MS, ESI-MS, MALDI
A 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.
In more detail
Mass spectrometry ionizes a sample and sorts the ions by mass-to-charge ratio. For a peptide, the result is compared with the theoretical molecular weight of the sequence. A match is strong evidence you have the right molecule. It is often run together with HPLC (LC-MS).
What it does not tell you: how pure the sample is, how much is in the vial, or whether it is sterile.
Why it matters
HPLC can show one clean peak that is the wrong peptide. Mass spec is the identity check that closes that gap.
Related terms
- HPLC purityThe 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.
- 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.
- 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.
Sources
Each source is labeled by where the information comes from. How we label sources
- Reference workMass spectrometry(opens in a new tab)
Wikipedia · checked
- Vendor guideWhat is peptide purity?(opens in a new tab)
LifeTein · checked
Updated