Analysis of complex polymers by MALDI-TOF mass spectrometry

Since the introduction by Karas and Hillenkamp in 1987 for the analysis of biomolecules, MALDI mass spectrometry has emerged to a powerful method for characterizing synthetic polymers. This soft ionization technique combined with time-of-flight mass analyzers is capable of providing a complete mass spectrum per event in a virtually unlimited mass range. Up to molar masses of about 30 000 g/mol mass-resolved polymer chains can be detected. From the oligomer masses the mass of the repeat units and the endgroups can be determined. For functionally heterogeneous systems detailed information on the functionality type distribution is available, while for copolymers sequence analysis can be conducted. The application of MALDI-TOF mass spectrometry to the analysis of homopolymers and heterogeneous polymers with respect to molar mass and chemical composition is demonstrated. It is shown that MALDI-TOF can be used efficiently for molar mass-sensitive detection in liquid chromatography.