Polyethylene and other polyolefins have not been amenable to mass spectrometric characterization of molecular mass distribution due to the ineffectiveness of conventional methods of cationization. The lack of polar groups, unsaturation, and aromaticity, excludes cationization methods that are used commonly for polymers. A new method is introduced in which an organic cation is covalently bonded to the polymer to produce the necessary ionization for successful matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry. A strong MALDI signal results from modified polymers that give no response in their unmodified form.