Structural effects on polyether cationization by alkali metal ions in matrix-assisted laser desorption/ionization

Structural effects on polyether cationization in matrix-assisted laser desorption/ionization (MALDI) are investigated using three different polyethers: PEG (polyethylene glycol), PPG (polypropylene glycol), and PTHF (polytetrahydrofuran). This study was performed using equimolar cesium and lithium chlorides as the cationizing agent. It was observed that the polyether structure variation led to a substantial change in polyether selectivity for alkali metal ion complexation. Moreover, it was found that like PEG, PPG displays a different selectivity for Cs+ and Li+ with different matrices. Discussion of these results and their implication in MALDI are given.