METAL-ION ATTACHMENT TO NONPOLAR POLYMERS DURING LASER-DESORPTION IONIZATION AT 337-NM

The attachment of metal ions to non-polar polymers is shown to be readily achieved using 337 nm laser desorption and ionization, with time-of-flight mass analysis, and could thus prove useful for the analysis of such polymers using commercially available matrix-assisted laser desorption/ionizatian instruments. Attachment of Cr+, Cu+ and Ag+ has been used successfully to increase the ion yield of polystyrene and polybutadiene during laser desorption/ionization. The metal ion used may originate from the metal sample holder substrate on which the polystyrene is placed, or from metal salts mixed with the polystyrene either prior to placement on the sample holder or in situ. Results have been obtained which illustrate metal-ion attachment to the polystyrene from the substrate and from a dopant salt simultaneously and the roles of each of these will be discussed.