Chlorine-functionalized TEMPO-capped polystyrenes were investigated using the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technique. Amine- and acrylate-functionalized agents and bifunctional TEMPO-capped polystyrene were also analyzed to demonstrate the applicability of this method. Using this technique allowed to analyze the conversion of the chlorine function to an acrylate function, which was previously difficult to detect with other methods.