1, Karlsruhe Institute of Technology (KIT), Karlsruhe, Baden-Wuerttemberg, Germany
Mass spectrometry (MS) provides the synthetic polymer chemist with a powerful tool to investigate the molecular structure of macromolecules. In the current lecture, the mass spectrometric analysis of classically challenging to ionize synthetic non-polar macromolecules is introduced. We introduce a powerful chloride attachment operating in negative ion mode to assess the precise chemical structure of the synthetic non-polar macromolecules. A supercharging effect is observed (i.e. detection of higher charge states than typically found) for hardly ionizable polymers such as polystyrene (PS) (ranging from 1700 g mol-1 to 18000 g mol-1), and – for the first time reported using ESI as ionization method – for poly(1,4-butadiene) ranging from 1000 g mol-1 to 10000 g mol-1. Up to quadruply charged PS species have been detected using a high-resolution MS protocol. Here, a systematic assessment of the manipulation of these charge states using supercharging agents (sulfolane, propylene carbonate and m-nitrobenzyl alcohol) is carried out and additionally applied to poly(2-vinylpyridine) and poly(acrylamide). Critically, the sensitive operation conditions for a successful supercharging effect have been identified. Further, our novel technology has been applied to highly polar polyelectrolytes, i.e. poly(ionic liquid)s.