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Updated: Jun 13, 2025
08:40
Using a Cyclic Ion Mobility Spectrometer for Tandem Ion Mobility Experiments
Published on: January 20, 2022
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Diastereomer Characterization of PS-Modified Synthetic Oligonucleotides Using Cyclic IMS-MS.
Edie M Sharon1, Sarah M O'Keefe1, Kathleen T Grassmyer2
1Department of Chemistry, Indiana University, Bloomington, Indiana 47401, United States.
Analytical Chemistry
|September 9, 2024
Summary
Characterizing phosphorothioate (PS) modified oligonucleotides is crucial for drug development. This study introduces a novel cyclic ion mobility spectrometry-tandem mass spectrometry (IMS-MS) method for analyzing PS oligonucleotide diastereomers without enzymatic digestion.
Area of Science:
- Oligonucleotide therapeutics
- Analytical chemistry
- Mass spectrometry
Background:
- Synthetic oligonucleotides are valuable therapeutics for gene expression regulation.
- Phosphorothioate (PS) linkages enhance oligonucleotide stability and performance.
- PS modifications create complex diastereomer mixtures, posing analytical challenges.
Purpose of the Study:
- To develop and demonstrate an analytical method for characterizing diastereomers in PS-modified oligonucleotides.
- To address the lack of current methods for measuring PS oligonucleotide diastereomers.
Main Methods:
- Utilized cyclic ion mobility spectrometry-tandem mass spectrometry (IMS-MS) on intact oligonucleotides.
- Employed top-down fragmentation in MS to generate smaller fragments with fewer diastereomers.
- Applied tandem IMS for mobility-based resolution of terminal diastereomers.
Main Results:
- Successfully elucidated diastereomer structures in four model PS-modified oligonucleotides.
- Demonstrated the capability of IMS-MS to analyze intact oligonucleotides without enzymatic digestion.
- Showcased mobility resolution of diastereomers at fragment ends.
Conclusions:
- The developed cyclic IMS-MS method provides a powerful tool for characterizing PS oligonucleotide diastereomers.
- This technique facilitates a deeper understanding of modified oligonucleotide structures for therapeutic applications.
- The method overcomes limitations of existing analytical techniques for PS-modified therapeutics.
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