Also called MS · mass spec · LCMS · LC-MS/MS
Mass spectrometry (MS) ionizes molecules and separates them by mass-to-charge ratio, producing a spectrum used to determine molecular mass. For peptides it is the gold-standard identity test: a measured mass matching the theoretical molecular weight (within ~0.02%) confirms the correct sequence was synthesized. HPLC-MS combines purity and identity in one run.
Research use only. This definition is an educational reference, not medical advice or dosing guidance.