Probing polystyrene cationization in matrix-assisted laser/desorption ionization

It has been observed that the use of the salts of transition metals other t han silver, copper or palladium as the cationizing agent, often fails to ca tionize polystyrenes in matrix-assisted laser/desorption ionization (MALDI) . This work shows that the ability of MALDI to reduce metals to the oxidati on state +1 is critically important to polystyrene cationization, Without t his reduction, MALDI tends to fail to form polystyrene-metal cations, In ad dition, this work demonstrates the importance of the use of a good combinat ion of metal salts and matrix in polystyrene cationization. Finally, the im plications of this work in the MALDI time-of-flight analysis of polystyrene s are discussed.