Presentation Profile
Characterization of highly dispersed polymers and their end groups by combining SEC/MALDI-TOFMS and Kendrick mass defect analysis
Currently Scheduled: 10/14/2025 - 8:55 AM - 9:15 AM
Room: Tulip
Main Author
Bryan Katzenmeyer - JEOL
- Takaya Satoh - JEOL
- Takafumi Sato - JEOL
- Kumiko Ikuta - TOSOH Analysis and Research Center Co.,Ltd.
- Yuko Matsubuchi - TOSOH Analysis and Research Center Co.,Ltd.
- Takayasu Hirai - TOSOH Analysis and Research Center Co.,Ltd.
- Nobuyuki Kagawa - TOSOH Analysis and Research Center Co.,Ltd.
- Tetsuya Sugimoto - S.T.Japan Inc.
- Tsuneo Kobayashi - S.T.Japan Inc.
Abstract:
Matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) is an effective method for analyzing polymers. However, polymers with high polydispersity can cause mass discrimination, where ion intensity decreases at higher molecular weights. We combined size-exclusion chromatography (SEC) with MALDI-TOFMS and MALDI-TOF/TOFMS to address this. In this report, we performed end-group analysis of polymer samples with high polydispersity and molecular weights below 50,000 using SEC and high-performance MALDI-TOFMS. We report (i) efficient MALDI pretreatment from SEC fractionation, (ii) improved visualization of end-group changes through remainder of Kendrick Mass (RKM) plots, and (iii) end-group analysis utilizing high mass accuracy and TOF/TOF measurements. Two polycaprolactone (PCL) samples with different end-groups were dissolved in THF and fractionated using SEC. Six fractions were collected, significantly decreasing the polydispersity index (PDI) from > 1.4 Ð to < 1.1 Ð. MALDI-TOFMS analysis revealed a series of PCL monomers and reduced mass discrimination, with isotopic peak separation achieved up to m/z 20,000, allowing precise end-group determination within < 2 ppm. Although the change in molecular weight distribution is easily observed in the mass spectra, understanding the changes in end-groups based on molecular weight is challenging. To visualize end-group changes, we converted the mass spectra into RKM plots. These plots clarified that cyclic oligomers dominated at low molecular weights, while higher weights exhibited two distinct mass distributions corresponding to different end-groups, identified as C4H10O and C4H10O3 through accurate mass and MS/MS (TOF/TOF) measurements.
