An interleaved comb ion deflection gate for m/z selection in time-of-flight mass spectrometry

Modulation of an ion beam is crucial to several applications in time-of-flight (TOF) mass spectrometry, especially for tandem TOF instruments which require selection of a particular precursor m/z (mass to charge) value prior to fragmentation. Here we present a detailed description of an ‘‘interleaved comb’’ ion deflection gate device with suitable electronics which offers a performance advantage over the more commonly used deflection plate devices. We demonstrate unit mass resolution for selection to m/z 167 in the tandem TOF instrument constructed in our laboratory. Calculations suggest that the real time of unit resolution for our experimental arrangement is greater than 300.