Rapid microscale analyses with an external ion source Fourier transform ion cyclotron resonance mass spectrometer

The design of a multi-purpose external ion source Fourier transform ion cyclotron resonance mass spectrometer for rapid microscale analyses of complex mixtures is presented. Rapid microscale analyses are carried out using several desorption and ionisation techniques, and benefit from a hydrocarbon-free UHV (Ultra High Vacuum) system. Two different techniques for polymer analysis will be discussed. ''In source'' filament pyrolysis is used for high speed, broadband screening of additives in polymer blends, and matrix assisted laser desorption and ionisation (MALDI) is used for endgroup analysis and molecular weight determination. External ion source MALDI measurements of the molecular weight distribution of an amine terminated poly(propyleneglycol) are shown to be extremely sensitive to the ion accumulation time used, as a result of the flight time distribution of the ions from ion source to analyser cell. Deconvolution of the measured transient shows that magnetron motion exhibits a strong mass dependent influence on the measured molecular weight distribution. This deconvolution and 2D-representation of the measured and Fourier transformed data provides additional insight into the ion behaviour inside the ICR cell.