Time-lag focusing MALDI time-of-flight mass spectrometry for polymer characterization: oligomer resolution, mass
R M Whittal1, D C Schriemer, L Li
1Department of Chemistry, University of Alberta, Edmonton, Canada.
Abstract:
We report a polymer characterization study by matrix-assisted laser description/ionization (MALDI) on a linear time-of-flight instrument equipped with pulsed ion extraction for time-lag focusing. It is demonstrated that time-lag focusing MALDI provides improved mass resolution and mass accuracy over continuous extraction instruments. Oligomer resolution is extended to a much higher mass range than that observed even by continuous extraction reflectron systems. This allows new opportunities to study the chemical composition and determine the molecular weight of individual components in a mixture of higher molecular weight polymers. It is shown that oligomer resolution can be obtained for poly(ethylene glycol) (repeat unit mass of 44) of mass up to 25,000 u and poly(styrene) (repeat unit mass of 104) up to 55,000 u. Mass measurement accuracy of 80 ppm or better is demonstrated, and the relevance to end-group analysis is shown for two derivative of poly(ethylene glycol) used as slow-release drugs. The analysis of the molecular weight distribution was investigated at several extraction pulse potentials to determine if there was an effect on the relative peak area. We found that the values of the number-average molecular weight (Mn and the weight-average molecular weight (Mw) do not change significantly for a poly(styrene) blend with oligomer masses between 2,000 and 15,000 u and a polydispersity of 1.155. The values are within the 1.6% standard deviation observed for repeat analyses at the same extraction pulse.
More Related Videos
06:56Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) Mass Spectrometry
Published on: June 10, 2018
06:16MALDI-ToF MS Method for the Characterization of Synthetic Polymers with Varying Dispersity and End Groups
Published on: October 3, 2025
Related Concept Videos
MALDI-TOF Mass Spectrometry
Peptide Identification Using Tandem Mass Spectrometry
This technique helps gather information regarding the protein from which the peptide was obtained and to study the peptides’ amino acid sequence. Identifying peptides from a complex mixture is an important component of the growing field of...
Tandem Mass Spectrometry
Matrix-Assisted Laser Desorption Ionization (MALDI)
Determination of Molar Masses of Polymers I
Determination of Molar Masses of Polymers II
