Chromatography
Definition
Any technique that separates a mixture by how its components distribute between a moving phase and a stationary one. Reversed-phase liquid chromatography is the version peptide work almost always means.
Where this term comes up
Entries whose definition mentions Chromatography.
What this means for research sourcing
Purity and identity verification are central to research reproducibility. Every Volta compound ships with >99% HPLC-verified purity and a certificate of analysis.
Related Terms in Quality
Mass Spectrometry (MS)
Measurement of the mass-to-charge ratio of ionised molecules, used to confirm that the observed mass matches the mass the sequence predicts. It supports identity; on its own it does not prove the full sequence, since rearrangements can share a mass.
Amino Acid Analysis (AAA)
Hydrolysing a peptide back to its constituent amino acids and quantifying each one, which gives composition and total peptide content. It answers a question HPLC does not: how much peptide is actually in the vial.
Net Peptide Content
The share of the powder that is peptide, once counter-ions and residual water are accounted for. Gross vial weight is always higher, so purity and content are two separate numbers and neither substitutes for the other.
Karl Fischer Titration
The standard volumetric assay for water content in a dry solid, using an iodine reaction specific to water. On a lyophilised peptide it reports residual moisture, which is a stability predictor, and it shares only its name with dose titration.
Purity
The proportion of a sample that is the intended peptide rather than related impurities, measured chromatographically and quoted as a percentage. It says nothing about identity, sterility or endotoxin content, each of which is a separate test. Volta releases every batch against a >99% HPLC specification.
Endotoxin
Lipopolysaccharide from the outer membrane of Gram-negative bacteria. It survives ordinary sterilisation and is not removed by filtration alone, and it provokes a febrile inflammatory response, which is why it is assayed separately from sterility.
LAL Test (Limulus Amebocyte Lysate)
The endotoxin assay, which uses a clotting cascade from horseshoe crab blood that endotoxin triggers. A result on a certificate is a quantity against a limit, not a yes or no.
Sterility Testing
Incubation of a sample in growth media to confirm no viable microorganism is present. Sterility is a property of a validated process and its container and is independent of chemical purity: a very pure material can be non-sterile and often is.