Preliminary matrix-assisted laser desorption ionization time-of-flight andfield desorption mass spectrometric analyses of polymeric methylene diphenylene diisocyanate, its amine precursor and a model polyether prepolymer

Matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometric analyses have been undertaken on the polyaromatic polyisocya nate methylene diphenylene diisocyanate (MDI) and its amine precursor. Thes e preliminary studies have shown that the MALDI-TOF spectra are complicated by the presence of intense ion peaks which are additional to the species o f interest. In comparison, the more experimentally demanding technique of f ield desorption mass spectrometry has produced spectra of superior quality and would appear to be the method of choice for continued development. A model poly(propylene glycol) based MDI prepolymer has been successfully e xamined using MALDI-TOFMS, the expected series of peaks corresponding to th e different PPG homologues being clearly observed with excellent signal-to- noise ratios in this experimentally convenient mass spectrometric technique . (C) 1998 John Wiley & Sons, Ltd.