Structural Analysis of Polymer End Groups by Electrospray Ionization High-Energy Collision-induced Dissociation Tandem Mass Spectrometry

摘要

Chemical siructures of polymer end groups play an important role in determining the functional properties of a polymeric system. We present a mass spectrometric method for determining end group structures. Polymeric ions are produced by electrospray ionization (ESI), and they are subject to source fragmentation in the ESI interface region to produce low-mass fragment ions. A series of source-fragment ions containing various num-bers of monomer units are selected for high-energy collision-induced dissociation (CII)) in a sector/time-of-flight tandem mass spectrometer. It is shown that high-energy CID spectra of source-induced fragment ions are veiy informative for end group structure characterization. By comparing the CID spectra of fragment ions with those of known chemicals, it is possible to unambiguously identify the end group structures. The utility of this technique is illustrated for the analysis of two poly-(ethylene glycol)-based slow-releasing drugs where de-tailed structural characterization is of significance for drug formulation, quality control, and regulatoiy approval. Practical issues related to the application of this method are discussed.