Detection method for dissociation of multiple-charged ions

A system for mass spectrometry of multiple-charged ions, the system comprising:

• means for multiply charging analyte ions;
• a dissociation cell for dissociating the multiple-charged ions to produce daughter fragments including a contemporaneous set of sibling ions for each dissociation event;
• mass spectrometer means for temporally dispersing the daughter fragments in accordance with a predetermined function of mass-to-charge m/z;
• detector means for detecting incidence of the daughter fragments including the sibling ions;
• timing means for determining time intervals between the incidences of the detected daughter fragments at the detector means;
• correlation means for correlation the incidences of at least the ionized daughter fragments to determine a set of sibling ions resulting from a single dissociation event and
• means for assigning simultaneous values of mass and charge to each of the sibling ions from their respective mass-to-charge ratios such that the assigned charges are substantially integer values and sum to the charge of the multiple-charged analyte ion.

An array-type mass spectrometer, comprising:

• a mass spectrograph with a nonscanning magnet for temporally and spatially dispersing ions along a focal surface in accordance with a predetermined function of m/z;
• an array detector extending along the focal surface for detecting incidences of the ions at a plurality of positions therealong;
• a plurality of readout means for sensing the positions of detected incidences of ions on the focal surface;
• means for sensing times of detected incidences of ions on the focal surface and producing time measurements of sufficient precision to determine flight time differences of different ions;
• and
• means coupling the time and position sensing means for associating the times and positions of incidence of ions detected on the focal surface.

An array detection system for mass spectrometry of multiple-charged ions, the system comprising:

• a dissociation cell for dissociating multiple-charged ions to produce a plurality of daughter fragments including a contemporaneous set of sibling ions for each dissociation event;
• a mass spectrograph for temporally and spatially dispersing ions along a focal surface in accordance with a predetermined function of mass-to-charge ratios m/z;
• an array detector extending along the focal surface for detecting incidences of the daughter fragments including said ions at a plurality of positions therealong;
• means for sensing the positions of the daughter fragments detected at the focal surface, the positions of the detected ions corresponding to their respective mass-to-charge ratios m/z;
• timing means for determining times of the incidences of detected daughter fragments at the detector means;
• means for associating the positions and times of detected ions at the focal surface;
• means for correlating the incidences of the detected ions to determine a set of sibling ions resulting from a single dissociation event.

A dual time-of-flight mass spectrometer, comprising:

• a single source of analyte ions;
• means defining a first, time-of-flight mass spectrometer and a second mass spectrometer each positioned to receive ions from said source and having a detector for producing a spectrum of detected ions;
• gating means for selecting the mass spectrometer into which the ions are transmitted;
• and
• means for sensing time of incidence of the ions on the detector;
• the gating and timing means being operable with a first duty cycle to direct a sample of the ions into the first mass spectrometer to produce a time-of-flight means spectrum showing a temporal dispersion of the ions according to their respective times of flight and being operable with a second duty cycle much greater than the first duty cycle to direct an approximately-continuous stream of the ions into the second mass spectrometer to produce a substantially continuous output of detection times of detected ions.

A dual time-of-flight system for mass spectrometry of multiple-charged ions, the system comprising:

• a dissociation cell for dissociating multiple-charged ions to produce a plurality of daughter fragments including a contemporaneous set of sibling ions for each dissociation event;
• first mass spectrometer means for transmitting a first sampled portion of the ions from said source to a first detector to detect the ions as dispersed according to their respective times of flight;
• first means for sensing times of incidence of the ions on the first detector, to determine the times of flight of ions in a mass spectrum thereof;
• second mass spectrometer means for transmitting an approximately continuous stream of the ions from said source to a detector;
• second means for sensing times of incidence of the ions on the second detector to generate a substantially continuous spectrum of the incidence times thereof;
• means for generating an autocorrelation spectrum from the continuous spectrum, showing a difference of times of flight of the ions;
• means for correlating the times of flight in the mass spectrum using the autocorrelation spectrum to determine a set of sibling ions resulting from a single dissociation event.