HPLC
High-performance liquid chromatography — the standard purity assay for research peptides.
High-performance liquid chromatography (HPLC) separates molecules in a sample by their interaction with a stationary phase (column packing) and mobile phase (eluent). For peptide purity testing, reverse-phase HPLC is standard: the peptide and any impurities elute at different retention times, and the area-under-curve of the main peak vs total peaks gives the purity percentage. A purity of >98% is the typical baseline for a research-grade peptide; >99% is high-end. The HPLC trace is part of the certificate of analysis (COA) that should accompany every research peptide.
- GlossaryMass spectrometry
Identifies a compound by measuring its mass-to-charge ratio.
- GlossaryCOA (Certificate of Analysis)
Document showing the analytical results — typically purity, mass, and identity — for a specific batch of research peptide.
- GlossaryHOMA-IR
A calculated index of insulin resistance from fasting glucose × fasting insulin.