Synthesis of a polyelectrolyte and its applications in laser desorption/ionization.

A novel laser energy-absorbing polymer derivatized from an energy-absorbing molecule has been synthesized. This polymer effectively eliminates the matrix addition step and the use of requisite small organic chemical matrixes from MALDI. The resulting polyelectrolyte-assisted laser desorption/ionization method has been proven to have some exceptional advantages over current MALDI methods. First, the matrix addition step from the LDI analytical process was eliminated. Second, the low molecular weight signal from energy-absorbing molecules was minimized by covalently linking the energy-absorbing molecules to the backbone of the polymer and other ionization-enhancing pendant groups on the backbone. Finally, the mass resolution of LDI was enhanced by minimizing chemical background noise throughout the spectrum. Polymeric linkage of energy-absorbing molecules aligns them with each other in an ordered structure, similar to MALDI matrix crystallization. Using the designed polymer film, laser desorption/ionization for proteins and peptides were successfully performed without the addition of any matrix. Analytical results for the synthesized monomer and polymers will be also presented.