Capitalizing on the high mass accuracy of electrospray ionization Fourier transform mass spectrometry for synthetic polymer characterization: A detailed investigation of poly(dimethylsiloxane)

We report on the use of electrospray ionization Fourier transform mass spectrometry (ESI-FTMS) toward the detailed analysis of a commercial poly(dimethylsiloxane) (PDMS) polymer sample. The high mass resolving power (accurate mass measurement), typical in FTMS analysis, allowed structural identification of all observed oligomeric manifolds. Such manifolds represent intact PDMS oligomers, various PDMS fragment ions, and polymer impurities. Further, we demonstrate the utility of nozzle-skimmer dissociation (NSD) not only in end-group analysis but also in the determination of whether an oligomeric distribution is the result of an energetic fragmentation route or is present as an impurity. Specifically, the relative ion intensities of the distribution of interest were examined before and after induced NSD conditions. Until recently, such ESI-FTMS techniques have been primarily used for the analysis of biopolymers. Taken in whole, these data demonstrate the utility of these methods toward the characterization of hydrophobic synthetic polymeric samples, structurally and mechanistically, with potential toward the investigation of real world polymeric samples.