The efficiency of dissocn. of macromol. ions during the capture of electrons in the ion trap of the ICR mass spectrometer is significantly enhanced by using an improved system of injection of low-energy electrons. The fragmentation time for an ion ensemble is decreased by more than an order of magnitude. This improvement makes possible anal. of peptides and proteins structures combined with their sepn. in by liq. chromatog. or capillary electrophoresis in real-time frame. [on SciFinder (R)]