A series of macrozwitterionic polymers have been prepared by anionic polymerisation using 2-[(dimethylamino)methyl]phenyl-lithium (DMPLi) as the initiator and 1,3-propanesultone as the terminating agent. Some observations are made on the problems associated with the synthesis of these materials, especially concerning the use of ethereal solvents and the implications these solvents have for the efficiency of the end-functionalisation reaction. Furthermore, we demonstrate that size exclusion chromatography of the sultone-terminated polymer not only allows molecular weight determination but also allows analysis of the yield of the end group functionalisation reaction at molecular weights up to 50,000 g mol(-1). At molecular weights of this magnitude, end group analysis by traditional methods such as NMR, IR, elemental analysis and even MALDI-MS would be of limited use.