Peptides are biological macromolecules composed of two or more amino acids linked by peptide bonds, exhibiting diverse biological functions. Tandem mass spectrometry (MS/MS) peptide sequencing identifies the amino acid composition and sequence of proteins or peptides using MS/MS. In the initial MS stage, peptide fragments are ionized and analyzed based on their mass-to-charge ratio (m/z), resulting in a MS1 that reflects the m/z and relative abundance of the peptide fragments.