Mass Spectrometry (MS) has become an indispensable tool for polymer analysis and has been widely used to study polymer structure, polymer composition, molecular weight and molecular weight distribution, bulk and surface properties, impurity contents, and so on. MS based on accurate mass measurement and/or tandem MS (MS/MS) analysis, can generate rich chemical information that is highly specific for polymer structural analysis. MS is also very sensitive, allowing the detection and identification of minor polymer components or impurities in a composed polymeric material and any by-product of polymerization reaction of a desired polymer or additives. Rapid MS analysis can be done for many polymer samples where no prior sample treatment or extensive separation is needed. MS can potentially provide semi quantitative information required for determination of the number average molecular weight and the weight average molecular weight of an oligomeric distribution of a polymer sample or a characterization of relative amounts of different components of a blend. Some forms of MS can also be used to characterize polymer surfaces.
Matrix assisted laser desorption ionization (MALDI) and electrospray ionization (ESI) MS has opened a new era in mass spectrometric analysis of biomolecules and synthetic polymer. ESI can be particularly useful for analyzing high mass molecules that are easy to form multiply charged gas phase ions and provide structural information for low molecular weight oligomers. In MALDI MS, “weight average” molecular weight and “number average” molecular weight information can be directly obtained for polymers of narrow polydispersity with high precision and speed as well as the determination of end groups. For high PD polymers SEC-MALDI has been established for accurate MW determinations. MALDI MS can also provide structural information and copolymer composition information, if the instrumental resolution is sufficient to resolve oligomers at the molecular weight range of interest.