A space-time buffer includes a plurality of discrete trapping regions and a controller. The plurality of discrete trapping regions is configured to trap ions as individual trapping regions or as combinations of trapping regions. The controller is configured to combine at least a portion of the plurality of trapping regions into a larger trap region; fill the larger trap region with a plurality of ions; split the larger trap region into individual trapping regions each containing a portion of the plurality of ions; and eject ions from the trapping regions.

A mass spectrometer system comprises: (a) an ion source; (b) a mass filter or a time-of-flight (TOF) ion separator configured to receive a stream of first-generation ions from the ion source; (c) an ion storage device having an ion inlet configured to receive a stream of filtered ions comprising a plurality of ion species from the mass filter or TOF separator and to accumulate the plurality of ion species therein; (d) an ion mobility cell having an ion inlet configured to receive an accumulated batch of ion species from the ion storage device and an ion outlet configured to release, one at a time, the individual ion species therefrom; and (e) a mass analyzer configured to receive and mass analyze each first-generation ion species or each fragment ion species generated by fragmentation or other reaction of the various first-generation ion species.

Disclosed herein are various methods and apparatus for performing charge detection mass spectrometry (CDMS). In particular, techniques are disclosed for monitoring a detector signal from a CDMS device to determine how many ions are present in the ion trap (10) of the CDMS device. For example, if no ions are present the measurement can then be terminated early. Similarly, if more than one ion is present, the measurement can be terminated early, or ions can be removed from the trap (10) until only a single ion remains. Techniques are also provided for increasing the probability of there being a single ion in the trap (10). A technique for attenuating an ion beam is also provided.

A time-of-flight mass spectrometer includes a flight tube, an ion introduction unit that is connected to the flight tube, an ion detector that detects an ion flown in the flight tube, and a control unit that controls the ion introduction unit and the flight tube, wherein: the control unit sequentially changes an accumulation state of the ion to be introduced into the flight tube by the ion introduction unit, for a plurality of measurement processes performed repeatedly.

In one aspect, a method of processing ions in a mass spectrometer is disclosed, which comprises trapping a plurality of ions having different mass-to-charge (m/z) ratios in a collision cell, releasing said ions from the collision cell in a descending order in m/z ratio, and receiving the ions in a mass analyzer having a plurality of rods to at least one of which an RF voltage is applied, where the RF voltage is varied from a first value to a lower second value as the released ions are received by the mass analyzer.

An instrument for analyzing ions may include an ion source to generate ions, at least one ion processing instrument to process the generated ions by one or both of filtering the ions according to a molecular characteristic and dissociating the ions, and an electrostatic linear ion trap (ELIT) to receive and trap ions exiting the at least one ion processing instrument. The ELIT has first and second ion mirrors separated by a charge detection cylinder, and is configured such that trapped ions oscillate back and forth through the charge detection cylinder between the first and second ion mirrors with a duty cycle, corresponding to a ratio of time spent by the trapped ions traversing the charge detection cylinder and total time spent by the trapped ions traversing a combination of the first and second ion mirrors and the charge detection cylinder during one complete oscillation cycle, of approximately 50%.

An electrostatic linear ion trap has first and second axially aligned ion mirrors separated by a charge detection cylinder axially aligned with each ion mirror. Electric fields are selectively established within the first and second ion mirrors in a manner which causes an ion in the trap to oscillate back and forth through the charge detection cylinder between the first and second ion mirrors with a duty cycle, corresponding to a ratio of time spent by the ion passing through the charge detection cylinder and total time spent traversing a combination of the first and second ion mirrors and the charge detection cylinder during one complete oscillation cycle, of approximately 50%.

A system for trapping ions for measurement thereof may include an electrostatic linear ion trap (ELIT), a source of ions to supply ions to the ELIT, a processor operatively coupled to ELIT, and a memory having instructions stored therein executable by the processor to produce at least one control signal to open the ELIT to allow ions supplied by the source of ions to enter the ELIT, determine an ion inlet frequency corresponding to a frequency of ions flowing from the source of ions into the open ELIT, generate or receive a target ion charge value, determine an optimum threshold value as a function of the target ion charge value and the determined ion inlet frequency, and produce at least one control signal to close the ELIT when a charge of an ion within the ELIT exceeds the optimum threshold value to thereby trap the ion in the ELIT.

In an embodiment of the present ambient ionization experiment, the abundance of background chemicals relative to ions of interest is decreased by pulsing the carrier gas used to generate the excited species directed at the sample. The excited species are stepwise directed at the sample reducing the overall abundance of background chemicals introduced into the ionizing region. In an embodiment of the present ambient ionization experiment, the combination of stepping the sample in front of the excited species and pulsing the carrier gas used to generate the excited species increases the sensitivity of detection.

In one aspect, a method of processing ions in a mass spectrometer is disclosed, which comprises trapping a plurality of ions having different mass-to-charge (m/z) ratios in a collision cell, releasing said ions from the collision cell in a descending order in m/z ratio, and receiving the ions in a mass analyzer having a plurality of rods to at least one of which an RF voltage is applied, where the RF voltage is varied from a first value to a lower second value as the released ions are received by the mass analyzer.