Analysis of poly(ethylene oxide)-b-poly(propylene oxide) block copolymers by MALDI-TOF mass spectrometry using collision induced dissociation

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to analyse the block length of commercially available block copolymers of poly(ethylene oxide) and poly (propylene oxide) (PEO-b-PPO) based on the fragmentation behaviour in collision induced dissociation (CID) experiments. MALDI-CID-TOF2 analysis is a complex procedure depending on a number of different experimental parameters. Therefore, a step-by-step procedure was used starting with PEG and PPG standards, PEG-PPG blends and endgroup-functionalized PPGs, to understand the fragmentation behaviour of the different species. These results showed that characteristic fragment patterns of the homopolymers and PEG-PPG mixtures can be obtained that facilitate the interpretation of the fragment spectra of PEO-b-PPO di- and triblock copolymers. It was found that di- and triblock copolymers can be differentiated by their fragment spectra. In addition, the sequence of monomer units in the diblock copolymers could be determined. (C) 2010 Elsevier Ltd. All rights reserved.