Mass spectrometry
Identifies a compound by measuring its mass-to-charge ratio.
Mass spectrometry (MS) ionises a sample and measures the mass-to-charge ratio (m/z) of the resulting ions. For peptides, MS confirms identity by showing that the measured molecular mass matches the theoretical mass calculated from the peptide's amino acid sequence. ESI-MS (electrospray ionisation) and MALDI-TOF are the most common methods for peptide analysis. MS complements HPLC: HPLC tells you how pure the sample is; MS tells you whether the main peak is the right molecule. A research-grade peptide COA usually includes both.
- GlossaryCOA (Certificate of Analysis)
Document showing the analytical results — typically purity, mass, and identity — for a specific batch of research peptide.
- GlossaryHPLC
High-performance liquid chromatography — the standard purity assay for research peptides.
- GlossaryHOMA-IR
A calculated index of insulin resistance from fasting glucose × fasting insulin.