Mass Spectrometry Explained
How ESI-MS confirms compound identity and what the observed vs. calculated mass comparison means.
Mass spectrometry (MS) is used to confirm the identity of a research compound by measuring its molecular mass. In electrospray ionization mass spectrometry (ESI-MS), the compound is ionized and the mass-to-charge ratio (m/z) is measured. The observed mass is then compared against the calculated theoretical mass for the compound.
A mass deviation of less than ±1 Da is generally considered acceptable for peptide identity confirmation. The COA will list the observed mass [M+H]⁺ (or other adduct), the calculated mass, and the deviation. Agreement between observed and calculated values confirms the correct compound was analyzed.
Mass spectrometry is used in conjunction with HPLC — together they provide both identity confirmation and purity assessment.
This content is provided for laboratory research purposes only and does not constitute medical, diagnostic, therapeutic, or veterinary guidance. All compounds are sold strictly for in vitro laboratory research use only.
