Time-lag focusing and cation attachment in the analysis of synthetic polymers by matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry

Ultraviolet matrix-assisted laser desorption/ionization-mass spectrometry has been employed with time-lag focusing to explore its utility for the characterization of synthetic polymers with broad distributions. Mixtures of five polymer standards with narrow molecular weight distributions were analyzed. The spectra were found to be broadly those expected for three different types of polymer systems-poly(styrene), poly(methyl methacrylate), and poly(ethylene glycol)-when equimass mixtures were used. Large changes in the apparent molecular weight distribution of poly(ethylene terephthalate) were observed when the cation was varied. The shift in the envelope was found to be related to the size and the ability of the oligomers to solvate the cation.