CHARACTERIZATION OF POLY(METHYL METHACRYLATE) BY MATRIX-ASSISTED-LASER-DESORPTION IONIZATION MASS-SPECTROMETRY - A COMPARISON WITH SUPERCRITICAL-FLUID CHROMATOGRAPHY AND GEL-PERMEATION CHROMATOGRAPHY/

The laser power dependence on matrix-assisted laser desorption/ionizat ion time-of-flight mass spectrometry (MALDI-TOFMS) has been studied by mixing equimolar amounts of three kinds of monodisperse poly(methyl m ethacrylate) (PMMA). Employing optimum laser power, the molecular weig ht information of the polydisperse PMMA was obtained, and the result c ompared with that obtained from supercritical fluid chromatography (SF C) and gel permeation chromatography (GPC). The average molecular weig ht of PMMA, obtained from the MALDI-MS experiment, was found to be hig her than that obtained from both SFC and GPC. The result implies that MALDI-MS can detect higher molecular species of the polymer. (C) 1998 John Wiley & Sons, Ltd.