TIME-LAG FOCUSING AND CATION ATTACHMENT IN THE ANALYSIS OF SYNTHETIC-POLYMERS BY MATRIX-ASSISTED LASER-DESORPTION IONIZATION-TIME-OF-FLIGHTMASS-SPECTROMETRY

Ultraviolet matrix-assisted laser desorption/ionization-mass spectrome try has been employed with time-lag focusing to explore its utility fo r the characterization of synthetic polymers with broad distributions. Mixtures of five polymer standards with narrow molecular weight distr ibutions were analyzed. The spectra were found to be broadly those exp ected for three different types of polymer systems-poly(styrene), poly (methyl methacrylate), and poly(ethylene glycol)-when equimass mixture s were used. Large changes in the apparent molecular weight distributi on of poly(ethylene terephthalate) were observed when the cation was v aried. The shift in the envelope was found to be related to the size a nd the ability of the oligomers to solvate the cation. (C) 1997 Americ an Society for Mass Spectrometry