Electrospray and Matrix-assisted Laser Desorption/Ionization Mass Spectrometry for the Characterization of Polyesters

Results for the analysis by matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) of low-mass polyesters with hydroxyl and ester end-groups are reported. After optimization of the experimental conditions, both methods produce reproducible mass spectra allowing the characterization of the various oligomers. However, a discrimination against the lower mass species, especially the monomers and the oligomers with n = 1, was observed. The influence of hydroxyl end-group esterification by trifluoroacetic acid on MALDI and ESI analyses was also studied. The results suggested the absence of a significant influence of the end-group in the MALDI and ESI processes. Furthermore, it allows the potential of each technique in polymer mixture characterization to be assessed.