Peptide Research Glossary: Key Terms Defined | Bio Mech

COA — Certificate of Analysis. HPLC — High-Performance Liquid Chromatography, the standard purity test. Mass spec — mass spectrometry, used to confirm peptide identity.

Lyophilised — freeze-dried powder. Bacteriostatic water — water with a small bacteriostatic agent, the most common reconstitution solvent. In-use stability — how long reconstituted product remains usable.

GLP-1 — glucagon-like peptide-1, a metabolic hormone target. GIP — glucose-dependent insulinotropic polypeptide, often paired with GLP-1 in dual agonists. Half-life — time for the compound's plasma concentration to halve.

Main peak — the chromatographic peak corresponding to the target sequence; its share of total peak area is the reported purity. Related substances — the identified and unidentified impurity peaks that remain; a good report lists them individually. Theoretical mass — the molecular weight calculated from the sequence, used as the reference for identity confirmation. Karl Fischer titration — the method behind the water-content line on a certificate.

Counter-ion / salt form — peptide acetates and other salt forms include counter-ion mass; a '5 mg acetate' vial contains less peptide by mass than '5 mg free base'. Peptide content / net peptide — the fraction of vial mass that is actual peptide, the figure quantitative work should calculate from. Endotoxin — a bacterial-membrane contaminant measured in units (EU/mg); relevant to cell-culture and in-vivo-adjacent work, usually absent from standard research COAs.

In-use stability — how long a reconstituted solution remains within specification under stated storage conditions. Lyophilisation — freeze-drying; the process that turns a peptide solution into the stable powder researchers receive. Aliquot — a divided single-use portion of a stock solution, the standard way to avoid repeated freeze-thaw cycles.

Batch / lot number — the production-run identifier printed on the vial; it is the key that connects a physical vial to its certificate. COA — Certificate of Analysis: the batch-linked document reporting purity, identity and content measurements. Independent (third-party) testing — analysis performed by a laboratory with no commercial interest in the result, such as Janoshik Analytical. Chain of custody — the documented path from production through testing to delivery.

RUO (research use only) — the labelling classification marking material as not for human or veterinary administration. Bacteriostatic water — sterile water with 0.9% benzyl alcohol, the standard multi-use reconstitution vehicle. Reconstitution — adding solvent to the lyophilised powder. Working stock — a diluted, labelled solution prepared from the reconstituted vial for actual bench use.