Poster Presentations
Day 3, June 12（Fri.） Room P (5F 501+502)
- 3P-03
Is ESI-MS really a soft ionization for biodegradable polymers? – EIC-based identification of in-source fragmentation by SEC-MS –
(1Mitsubishi Chemical, 2Amsterdam Univ, 3CASA)
oMasashi Serizawa1,2,3, Peter Schoenmakers2,3, Andrea Gargano2,3
Poly(lactide co glycolide) (PLGA) is a biodegradable polyester widely used in drug delivery systems, where not only the molecular weight distribution but also the chemical composition distribution and end group distribution critically govern performance. Although electrospray ionization (ESI) is generally considered a “soft” ionization technique, degradable polymers can undergo in source fragmentation, complicating the discrimination between intact polymer ions and fragments. Here, we introduce a simple, generalizable strategy to determine fragmentation in SEC HRMS by leveraging extracted ion chromatogram (EIC) profiles. For PLGA, we systematically detect signals of identical m/z that emerge at retention times inconsistent with the expected SEC elution region, and annotate them as in source fragments. This EIC based criterion improves the reliability of chemical composition and end group analyses. We further provide practical guidelines for minimizing fragmentation during ESI MS: across Li⁺, Na⁺, K⁺, Rb⁺, and Cs⁺ adducts, heavier alkali metal ions progressively suppress fragmentation; in addition, Sampling Cone voltage (as a proxy for ionization energy) strongly correlates with the extent of in source fragmentation. These optimization insights will be presented as an operational guide. Finally, using ESI conditions tuned by the EIC based diagnosis, we demonstrate robust applications to chemical composition distribution, end group distribution, and sequence level blockiness evaluation for PLGA.