Development of mass spectrometric glycan characterization tags using acid-base chemistry and/or free radical chemistry

Rayan Murtada, Shane Finn, Jinshan Gao

Research output: Contribution to journalReview articlepeer-review

1 Scopus citations


Despite recent advances in glycomics, glycan characterization still remains an analytical challenge. Accordingly, numerous glycan-tagging reagents with different chemistries were developed, including those involving acid-base chemistry and/or free radical chemistry. Acid-base chemistry excels at dissociating glycans into their constituent components in a systematic and predictable manner to generate cleavages at glycosidic bonds. Glycans are also highly susceptible to depolymerization by free radical processes, which is supported by results observed from electron-activated dissociation techniques. Therefore, the free radical activated glycan sequencing (FRAGS) reagent was developed so as to possess the characteristics of both acid-base and free radical chemistry, thus generating information-rich glycosidic bond and cross-ring cleavages. Alternatively, the free radical processes can be induced via photodissociation of the specific carbon-iodine bond which gives birth to similar fragmentation patterns as the FRAGS reagent. Furthermore, the methylated-FRAGS (Me-FRAGS) reagent was developed to eliminate glycan rearrangements by way of a fixed charged as opposed to a labile proton, which would otherwise yield additional, yet unpredictable, fragmentations including internal residue losses or multiple external residue losses. Lastly, to further enhance glycan enrichment and characterization, solid-support FRAGS was developed.

Original languageEnglish
Pages (from-to)269-288
Number of pages20
JournalMass Spectrometry Reviews
Issue number2
StatePublished - 1 Mar 2024


  • acid-base chemistry
  • free radical chemistry
  • glycan characterization
  • glycan enrichment
  • glycans
  • mass spectrometry


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