Glossary
Definitions of the terms used on certificates of analysis and in peptide research.
- Counter-ion
- A counter-ion is the oppositely charged ion, most often trifluoroacetate, that pairs with a synthetic peptide's charged residues and stays in the powder as part of its weight.
- High-performance liquid chromatography
- High-performance liquid chromatography (HPLC) separates the components of a sample on a packed column and is the standard method for measuring a peptide's chromatographic purity.
- Lyophilization
- Lyophilization, or freeze-drying, removes water from a frozen peptide solution under vacuum so the peptide is left as a dry, stable powder.
- Mass spectrometry
- Mass spectrometry measures the mass of a sample's molecules, and on a peptide certificate it is the test that confirms the main compound has the molecular weight of the peptide on the label.
- Net peptide content
- Net peptide content is the share of a lyophilized powder's total weight that is peptide, as opposed to water and counter-ions.
- Reference standard
- A reference standard is an authenticated sample of a compound that a laboratory runs alongside a test sample to confirm the sample's identity.