Peptides break mainly along the backbone, between residues. Fragments that keep the N-terminus are b ions (or c ions, by electron-transfer dissociation), and fragments that keep the C-terminus are y ions (or z ions). Neighboring ions in a series differ by the mass of one residue, so the series reads the sequence.
Leucine and isoleucine, and D- and L-forms, give the same fragment masses and are not distinguished this way.
See also
Cite this page
Text
Cosmic Peptides. (2026, October 25). Tandem mass spectrometry: glossary entry. Cosmic Peptides Research Library. Retrieved October 26, 2026, from https://cosmicpeptides.com/research/glossary/tandem-mass-spectrometry
BibTeX
@misc{cosmicpeptides_research_glossary_tandem_mass_spectrometry,
author = {{Cosmic Peptides}},
title = {Tandem mass spectrometry: glossary entry},
howpublished = {Cosmic Peptides Research Library},
year = {2026},
month = oct,
url = {https://cosmicpeptides.com/research/glossary/tandem-mass-spectrometry},
urldate = {2026-10-26},
note = {Last reviewed 2026-10-25}
} RIS
TY - ELEC AU - Cosmic Peptides TI - Tandem mass spectrometry: glossary entry T2 - Cosmic Peptides Research Library PB - Cosmic Peptides PY - 2026 DA - 2026/10/25 UR - https://cosmicpeptides.com/research/glossary/tandem-mass-spectrometry Y2 - 2026/10/26 LA - en ER -
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