ELECTROSPRAY AND MATRIX-ASSISTED LASER DESORPTION IONIZATION MASS-SPECTROMETRY FOR THE CHARACTERIZATION OF POLYESTERS/

Results for the analysis by matrix-assisted laser desorption/ionizatio n (MALDI) and electrospray ionization (ESI) of low-mass polyesters wit h hydroxyl and ester end-groups are reported. After optimization of th e experimental conditions, both methods produce reproducible mass spec tra allowing the characterization of the various oligomers. However, a discrimination against the lower mass species, especially the monomer s and the oligomers with n = 1, was observed, The influence of hydroxy l end-group esterification by trifluoroacetic acid on MALDI and ESI an alyses was also studied, The results suggested the absence of a signif icant influence of the end-group in the MALDI and ESI processes, Furth ermore, it allows the potential of each technique in polymer mixture c haracterization to be assessed.