The ultrasonic degradation products of poly(ethylene oxide)-poly(propylene oxide) diblock copolymers were characterized by MALDI-TOF-MS and high resolution mass spectrometry. Several ions in the products could not be assigned by MALDI-TOF-MS because of its low mass resolution. However, using high resolution mass spectrometry it was determined whether the end-group of these ions is oxo or ethoxy structure. The mass spectra obtained with high mass resolution are useful information for detailed analyses of repeat unit and end-group of the ultrasonic degradation products.
