Application of an integrated matrix-assisted laser desorption/ionization time-of-flight, electrospray ionization mass spectrometry and tandem mass spectrometry approach to characterizing complex polyol mixtures

Polyols are being used in a wide range of industrial applications including surfactants and precursors for grafted polymers. The characterization of p olyols is of significance in correlating compositions and structures with t heir properties. We illustrate two real world examples where traditional an alytical methods including GPC and NMR failed to reveal compositional diffe rences, but the combination of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF), electrospray ionization mass spectrometry (ESI MS), and MS/MS can produce compositional information required for problem s olving. The first example involves failure analysis of four ethylene oxide and propylene oxide (EO/PO) copolymer products. The results from the mass s pectrometry analysis unequivocally demonstrate that one of the samples has a small variation incopolymer composition, leading to its abnormal activity . The second example is in the area of deformulation of complex polyol mixt ures. Two samples displaying similar properties and activities were found t o be two different polyol blends. One of the samples is a more rest-effecti ve product. These examples demonstrate that MALDI, ESI MS, and MS/MS should be seriously considered as an integrated component of an overall polyol ch aracterization program in product failure analysis and deformulation. (C) 2 001 American Society for Mass Spectrometry.