Mass Spectrometry (MS)
An analytical method that measures mass-to-charge ratios to confirm peptide identity.
Definition
An analytical method that measures the mass-to-charge ratio of ions. Used in peptide analysis to determine molecular weight, confirm identity, and detect post-translational modifications with high accuracy.
In More Detail
A mass spectrometer ionizes a sample, separates the resulting ions by their mass-to-charge ratio (m/z), and measures their abundance. The output is a mass spectrum where each peak represents an ion of a specific m/z. For peptides, the observed mass is compared to the theoretical mass calculated from the amino acid sequence. A match within a few parts per million confirms identity, while mass shifts can reveal modifications like oxidation (+16 Da), deamidation (+1 Da), or truncation.