T. Yalcin et al., Structural analysis of polymer end groups by electrospray ionization high-energy collision-induced dissociation tandem mass spectrometry, ANALYT CHEM, 72(16), 2000, pp. 3847-3852
Chemical structures of polymer end groups play an important role in determi
ning the functional properties of a polymeric system. We present a mass spe
ctrometric method for determining end group structures. Polymeric ions are
produced by electrospray ionization (ESI), and they are subject to source f
ragmentation in the ESI interface region to produce low-mass fragment ions.
A series of source-fragment ions containing various numbers of monomer uni
ts are selected for high-energy collision-induced dissociation (CID) in a s
ector/time-of-flight tandem mass spectrometer. It is shown that high-energy
CID spectra of source;induced fragment ions are very informative for end g
roup structure characterization. By comparing the CID spectra of fragment i
ons 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
detailed structural characterization is of significance for drug formulati
on, quality control, and regulatory approval. Practical issues related to t
he application of this method are discussed.