RESUMEN
The inclusion of an ion gate in a tandem mass spectrometer allows a specific precursor ion to be selected, and the fragment ions are then used for structure analysis and to investigate chemical reactions. However, the performance of an ion gate has been judged simply by whether or not the target ion was selected. In this study, we designed, manufactured, constructed, and characterized a Bradbury-Nielsen ion gate (BNG). The actual ion selection ability, i.e. the gate function, of the BNG was measured for isotopes of Xez+ (z=1-6). The gate function of the BNG was 36.5±0.5â ns in width and 3-13â ns in rise and fall times. The BNG provides a simple way to select multiply charged molecular cations of small organic molecules as well as large molecules such as proteins and peptides.