Frequency and amplitude scanned quadrupole mass filter and methods

A quadrupole mass filter comprising:

• a quadrupole,
• an ionization source configured to ionize a sample to provide ions to the quadrupole,
• a detector coupled to the quadrupole for detecting ions passing therethrough,
• at least one AC voltage source,
• drive circuitry configured coupled to the quadrupole and to the at least one AC voltage source, and
• a computer programmed to control the drive circuitry to apply at least one AC voltage produced by the at least one AC voltage source to the quadrupole to separate the ions by (i) incrementally varying a frequency of the at least one AC voltage within a first range of frequencies and (ii) for each of at least some of the incremental frequencies in the first range of frequencies, incrementally varying an amplitude of the at least one AC voltage within a range of amplitudes, such that each incremental frequency and incremental amplitude pair of the at least one AC voltage creates a different band pass filter in the quadrupole through which ions having a different corresponding mass-to-charge ratio pass to the detector.