ANALYSIS OF POLY(STYRENESULFONIC ACID) BY MATRIX-ASSISTED LASER-DESORPTION IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETRY

Matrix-assisted laser desorption/ionization time-of-flight (MALDI/TOF) mass spectrometry has been used for the analysis of poly(styrenesulfo nic acid), and the molecular weight distributions have been determined for polymers up to 430 000 Da in mass. Poly(styrenesulfonic acid) and the sodium salt of the poly(styrenesulfonate) were analyzed by MALDI/ TOF with detection of negative or positive ions, respectively. The sin gly charged and several multiply charged distributions were observed f or polymers of average molecular weight 18 000, 100 000, and 400 000 D a. Agreement with the manufacturer's values for average molecular weig ht is good with the exception of the 18 000 Da sample which MALDI/TOF indicated was only partially sulfonated. This was confirmed by element al analysis.