Abstract: A mass spectrometry method in which an improved field comprising two or more trapping fields having substantially identical spatial form is established and at least one parameter of the improved field is changed to excite selected trapped ions sequentially for detection. The changing improved field (preferably with a supplemental field superimposed therewith) can sequentially eject selected ones of the trapped ions from the improved field for detection. An improved field comprising two quadrupole trapping fields can be established in a region defined by the ring and end electrodes of a three-dimensional quadrupole ion trap, and the amplitude of an RF (and/or DC) component (and/or the frequency of the RF component) of one or both trapping fields can be changed to sequentially excite trapped ions.

Abstract: A mass spectrometry method in which an improved field comprising two or more trapping fields having substantially identical spatial form is established and at least one parameter of the improved field is changed to excite selected trapped ions sequentially for detection. The changing improved field (preferably with a supplemental field superimposed therewith) can sequentially eject selected ones of the trapped ions from the improved field for detection. An improved field comprising two quadrupole trapping fields can be established in a region defined by the ring and end electrodes of a three-dimensional quadrupole ion trap, and the amplitude of an RF (and/or DC) component (and/or the frequency of the RF component) of one or both trapping fields can be changed to sequentially excite trapped ions.

Abstract: A mass spectrometry method in which an improved field comprising two or more trapping fields having substantially identical spatial form is established and at least one parameter of the improved field is changed to excite selected trapped ions sequentially for detection. The changing improved field (preferably with a supplemental field superimposed therewith) can sequentially eject selected ones of the trapped ions from the improved field for detection. An improved field comprising two quadrupole trapping fields can be established in a region defined by the ring and end electrodes of a three-dimensional quadrupole ion trap, and the amplitude of an RF (and/or DC) component (and/or the frequency of the RF component) of one or both trapping fields can be changed to sequentially excite trapped ions.

Abstract: A mass spectrometry method in which an improved field comprising two or more trapping fields having substantially identical spatial form is established and at least one parameter of the improved field is changed to excite selected trapped ions sequentially for detection. The changing improved field (preferably with a supplemental field superimposed therewith) can sequentially eject selected ones of the trapped ions from the improved field for detection. An improved field comprising two quadrupole trapping fields can be established in a region defined by the ring and end electrodes of a three-dimensional quadrupole ion trap, and the amplitude of an RF (and/or DC) component (and/or the frequency of the RF component) of one or both trapping fields can be changed to sequentially excite trapped ions.

Abstract: A method and apparatus is described which determines a plurality of spaced discrete frequencies covering the range of frequencies of the characteristic motion of unwanted ions and processes said discrete frequencies to generate a plurality of time dependent voltage amplitude values which vary throughout the time domain such that the frequency content of said plurality of time dependent voltage amplitude values is relatively uniform over the entire time domain, and such that the magnitude associated with the discrete frequencies is relatively uniform over the frequency domain.

Abstract: A method is disclosed for operating an ion trap mass spectrometer in such a way as to distinguish resonantly ejected ions from non-resonantly ejected ions. A supplementary AC field is superimposed on the three-dimensional quadrupole trapping field and the combined fields are scanned to resonantly eject ions of consecutive mass-to-charge ratio. The ejected ions are detected and the output signal of the resonantly ejected ions has a frequency component at the frequency of the supplementary AC field.

Abstract: A method of mass analyzing a sample including the steps of defining a trap volume with a three-dimensional quadrupole field for trapping ions within a predetermined range of mass-to-charge ratio, forming or injecting ions within the trap volume such that those within the predetermined mass-to-charge ratio range are trapped within the trap volume, applying a supplementary AC field superimposed on the three-dimensional quadrupole field to form combined fields, scanning the combined fields to eject ions of consecutive mass-to-charge ratio from the trap volume for detection characterized in that the supplementary field has an amplitude just sufficient to eject the ions and that the supplementary field has a beta value below 0.891 and that the combined fields are scanned at a rate so that a length of time corresponding to 200 cycles or more of the supplementary AC field passes per consecutive thomson.

Abstract: A simple and economical method of mass analyzing a sample by means of a quadrupole ion trap mass spectrometer in an MS/MS mode comprises the steps of forming ions within a trap structure, changing the RF and DC voltages in such a way that the ions with mass-to-charge ratios within a desired range will be and remain trapped within the trap structure, dissociating such ions into fragments by collisions and increasing the field intensity again so that the generated fragments will become unstable and exit the trap volume sequentially to be detected. A supplementary AC field may be applied additionally to provide various scan modes as well as dissociate the ions.

Abstract: The method of performing chemical ionization and mass analysis with a quadrupole ion trap.

Abstract: A simple and economical method of mass analyzing a sample by means of a quadrupole ion trap mass spectrometer in an MS/MS mode comprises the steps of forming ions within a trap structure, changing the RF and DC voltages in such a way that the ions with mass-to-charge ratios within a desired range will be and remain trapped within the trap structure, dissociating such ions into fragments by collisions and increasing the field intensity again so that the generated fragments will become unstable and exit the trap volume sequentially to be detected. A supplementary AC field may be applied additionally to provide various scan modes as well as dissociate the ions.