The invention generally relates to systems and methods for isolating a target ion in an ion trap. In certain aspects, the invention provides a system that includes a mass spectrometer having an ion trap, and a central processing unit (CPU). The CPU includes storage coupled to the CPU for storing instructions that when executed by the CPU cause the system to apply a dual frequency waveform to the ion trap that ejects non-target ions from the ion trap while retaining a target ion in the ion trap.