ELECTROSPRAY-IONIZATION MASS-SPECTROMETRIC STUDY OF OLIGOMERIC LINEARPOLYSULFIDES - CHARACTERIZATION OF REPEAT UNITS, END-GROUPS AND FRAGMENTATION PATHWAYS

Electrospray ionization mass spectrometry is shown to offer excellent characterization of linear oligomeric polysulfides H(SC2H4OCH2OC2H4S)( n)H with n = 1-24. Analysis of the mass spectra reveals the presence o f individual oligomers, the presence in certain oligomers of repeat un its containing additional oxyalkylene groups (and in some cases a mono sulfide link rather than disulfide) and the presence of end groups suc h as epoxy. The attachment of polyacrylates during cure can also be de tected. Assignments of individual peaks can be confirmed by collision- induced decomposition and precursor ion experiments: the fragmentation pathways are relatively few except for linear polysulfides of complex structure. The best signal-to-noise conditions are achieved with low- to-medium cone voltages and a mobile phase of acetone containing 0.5% KI. (C) 1997 Elsevier Science Ltd.